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  • 1.
    Ako, Thomas
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Design of invisibility cloaks with an open tunnel2010In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 18, no 26, p. 27060-27066Article in journal (Refereed)
    Abstract [en]

    In this paper we apply the methodology of transformation optics for design of a novel invisibility cloak which can possess an open tunnel. Such a cloak facilitates the insertion (retrieval) of matter into (from) the cloak's interior without significantly affecting the cloak's performance, overcoming the matter exchange bottleneck inherent to most previously proposed cloak designs. We achieve this by applying a transformation which expands a point at the origin in electromagnetic space to a finite area in physical space in a highly anisotropic manner. The invisibility performance of the proposed cloak is verified by using full-wave finite-element simulations. (C) 2010 Optical Society of America

  • 2.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dai, Jin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zhao, Ding
    Li, Qiang
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Ordered Au nanocrystals on a substrate formed by light-induced rapid annealing2014In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 6, no 3, p. 1756-1762Article in journal (Refereed)
    Abstract [en]

    Light-induced rapid annealing (LIRA) is a widely used method to modify the morphology and crystallinity of noble metal nanoparticles, and the nanoparticles generally evolve into nanospheres. It is rather challenging to form faceted Au nanocrystals on a substrate using LIRA. Here the formation of spatially ordered Au nanocrystals using a continuous wave infrared laser is reported, assisted by a metamaterial perfect absorber. Faceted Au nanocrystals in truncated-octahedral or multi-twinned geometries can be obtained. The evolution of morphology and crystallinity of the Au nanoparticles during laser annealing is also revealed, where the crystal grain growth and the surface melting are shown to play key roles in nanocrystal formation. The evolution of morphology also gives the freedom of tuning the absorption spectrum of the metamaterial absorber. These findings provide a novel way for tailoring the morphology and crystallinity of metallic nanoparticles and may pave the way to fabricate refined nano-devices in many potential applications for optics, electronics, catalysis, surface-chemistry and biology.

  • 3.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Shi, Yuechun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Zhejiang University, China.
    Photothermal switching of SOI-waveguide-based Mach-Zehnder interferometer with integrated plasmonic nanoheater2014In: Plasmonics, ISSN 1557-1963, Vol. 9, no 5, p. 1197-1205Article in journal (Refereed)
    Abstract [en]

    We theoretically and numerically investigate photothermal switching of a Mach-Zehnder interferometer (MZI) based on two Si waveguides integrated with plasmonic nanoheater. The nanoheater is a composite nanowire with Au/Al2O3/Au three-layer structure, which is designed to have a high-efficient optical absorption peak at wavelength of 1064 nm. Based on this finding, we further analyze a MZI built with two 40 μm-long symmetric waveguide branches, each integrated with a 20 μm-long nanoheater. The optical switching power of the MZI device is 190 mW (280 mW) for the capped (buried) channel waveguide, when pumped by a circular Gaussian beam with a waist of 10 μm. Alternatively, the switching power can be reduced to 38 mW (56 mW) by using an astigmatic Gaussian beam, with a semi-major axis of 10 μm and an aspect ratio of 5. The switching response time of the MZI is 0.7 μs (1.0 μs) for capped (buried) channel waveguide design. Our design opens a new route for optically driven non-contact optical on-off switching with sub-microsecond time response.

  • 4.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Nanosecond Photothermal Effects in Plasmonic Nanostructures2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 3, p. 2550-2557Article in journal (Refereed)
    Abstract [en]

    Photothermal effects in plasmonic nanostructures have great potentials in applications for photothermal cancer therapy, optical storage, thermo-photovoltaics, etc. However, the transient temperature behavior of a nanoscale material system during an ultrafast photothermal process has rarely been accurately investigated. Here a heat transfer model is constructed to investigate the temporal and spatial variation of temperature in plasmonic gold nanostructures. First, as a benchmark scenario, we study the light-induced heating of a gold nanosphere in water and calculate the relaxation time of the nanosphere excited by a modulated light. Second, we investigate heating and reshaping of gold nanoparticles in a more complex metamaterial absorber structure induced by a nanosecond pulsed light. The model shows that the temperature of the gold nanoparticles can be raised from room temperature to >795 K in just a few nanoseconds with a low light luminance, owing to enhanced light absorption through strong plasmonic resonance. Such quantitative predication of temperature change, which Is otherwise formidable to measure experimentally, can serve as an excellent guideline for designing devices for ultrafast photothermal applications.

  • 5.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Cui, T.
    Photothermal direct writing of metallic microstructure for frequency selective surface at terahertz frequencies2012In: Proceedings of the 2012 International Workshop on Metamaterials, Meta 2012, IEEE , 2012, p. 6464923-Conference paper (Refereed)
    Abstract [en]

    Maskless photothermal direct writing technique was investigated to fabricate planar microscale metallic structures. In this technique, we use a tightly focused nanosecond pulsed infrared light to heat the metallic thin film on substrate. With sufficient volumic power density, the metal inside a "hot spot" could be removed from substrate. This technique benefits from not only the enhanced optical absorption, thanks to the surface plasmon resonance of metallic thin film, but also the reduced thermal conductivity, due to the frequent boundary scattering of phonons inside the thin film. To verify the performance of our direct writing technique, a cross-slot periodic array is scribed in gold thin film on silica substrate. Such a pattern can serve as a frequency selective surface at terahertz, which has many applications in terahertz radio system, e. g. rejecting thermal noise before terahertz receiver or serving as reflectors in Fabry-Perot etalon for astronomy spectroscopy.

  • 6.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wang, Jing
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Hao, Jiaming
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Photothermal phenomena in plasmonics and metamaterials2011In: ADVANCES IN OPTICAL THIN FILMS IV, 2011, p. 81681K-Conference paper (Refereed)
    Abstract [en]

    Our recent theoretical and experimental investigation of the photothermal effect in a planar metamaterial absorber is reviewed in the present paper. The observed ultrasensitive photothermal heating in such an absorber nanostructure irradiated by a pulsed white-light source is elaborated with a simple yet compelling heat transfer model, which is subsequently solved with a finite-element method. The simulation results not only agree with the experimental finding, but also provide more detailed understanding of the temperature transition in the complex system.

  • 7.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Shi, Yuechun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Lou, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Zhejiang University, China.
    Photothermally tunable silicon microring-resonator-based optical add-drop filterManuscript (preprint) (Other academic)
    Abstract [en]

    A themro-optic (TO) silicon photonic add-drop filterwith small switching power and fast response is experimentallydemonstrated. We propose that metal-insulator-metal (MIM)absorbers can be integrated into the silicon TO devices, acting asan efficient and localized heat source. The MIM absorber designintroduces less thermal capacity to the device, comparing to theelectrically driven heater used in conventional TO devices. As a keyelement in silicon photonics, microring resonators have applicationin wavelength-division-multiplexing (WDM) devices, owning to theirunique spectrum properties. In this work, a silicon microring add-dropfilter is equipped with a MIM absorber. Experimentally, the deviceshows a measured optical response time of 5.0 μs and pumping powerderivative of the wavelength shift of 60 pm/mW.

  • 8.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Shi, Yuechun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Nanjing University, China.
    Lou, Fei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Zhejiang University, China.
    Photothermally tunable silicon-microring-based optical add-drop filter through integrated light absorber2014In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 22, no 21, p. 25233-25241Article in journal (Refereed)
    Abstract [en]

    An optically pumped thermo-optic (TO) silicon ring add-drop filter with fast thermal response is experimentally demonstrated. We propose that metal-insulator-metal (MIM) light absorber can be integrated into silicon TO devices, acting as a localized heat source which can be activated remotely by a pump beam. The MIM absorber design introduces less thermal capacity to the device, compared to conventional electrically-driven approaches. Experimentally, the absorber-integrated add-drop filter shows an optical response time of 13.7 mu s following the 10%-90% rule (equivalent to a exponential time constant of 5 mu s) and a wavelength shift over pump power of 60 pm/mW. The photothermally tunable add-drop filter may provide new perspectives for all-optical routing and switching in integrated Si photonic circuits.

  • 9.
    Chen, Yiting
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dai, Jin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Honeycomb-lattice plasmonic absorbers at NIR: anomalous high-order resonance2013In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, no 18, p. 20873-20879Article in journal (Refereed)
    Abstract [en]

    We design, fabricate and characterize a plasmonic honeycomb lattice absorber with almost perfect absorption at 1140 nm over a wide incident angle range. This absorber also possesses a narrow-band, angle-and polarization-dependent high-order resonance in the short-wavelength range, with a bandwidth of 19 nm and angle sensitivity of 3 nm per degree. The nature of this high-order absorption band is analyzed through finite-element simulations. We believe it is due to Bragg coupling of the incident light to the backward-propagating surface plasmon polariton through the periodic modulation of the structure. Such fine absorption bands can find applications in plasmonic sensors and spectrally selective thermal emitters.

  • 10.
    Chen, Yiting
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dai, Jin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Influence of latticestructure on metal-insulator-metal plasmonic absorbersManuscript (preprint) (Other academic)
  • 11.
    Chen, Yiting
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dai, Jin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Zhejiang University, China .
    Metal-insulator-metal plasmonic absorbers: influence of lattice2014In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 22, no 25, p. 30807-30814Article in journal (Refereed)
    Abstract [en]

    We experimentally demonstrate three kinds of metal-insulator-metal based plasmonic absorbers consisting of arrays of gold nanodisks distributed in different lattices, including square, triangular and honeycomb lattices. It's found that resonances originated from localized surface plasmon undergo little changes with respect to different lattice distributions of the nanodisks. The interparticle coupling results in a minor bandwidth broadening of the fundamental mode. Different from square-and triangular-lattice absorbers, honeycomb-lattice absorber possesses a unique red-shifting (with respect to incident angles) narrow-band high-order mode, which originates from coupling of incident light to propagating surface plasmon polariton (SPP) waves. Similar high-order mode can also be generated in square-lattice absorber by increasing the period so that a smaller reciprocal lattice vector can be introduced to excite the SPP mode. Furthermore, we show that two types of resonances can interact and create Fano-type resonances. The simulation results agree well with the experimental results. (C) 2014 Optical Society of America

  • 12.
    Chen, Yiting
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Wang, Jing
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Xi
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Plasmonic analog of microstrip transmission line and effect of thermal annealing on its propagation loss2013In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, no 2, p. 1639-1644Article in journal (Refereed)
    Abstract [en]

    We fabricated a plasmonic analog of the microwave microstrip transmission line and measured its propagation loss before and after thermal annealing. It is found that its propagation loss at 980 nm wavelength can be reduced by more than 50%, from 0.45 to 0.20 dB/μm, after thermal annealing at 300 °C. The reduction in loss can be attributed to the improved gold surface condition and probably also to the change in the metal's inner structure. Less evident loss reduction is noticed at 1550 nm, which is owing to extremely small portion of the modal electric field located in the metal regions at this wavelength.

  • 13.
    Dai, Jin
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Ding, Fei
    Bozhevolnyi, Sergey I.
    Yan, Min
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Ultrabroadband super-Planckian radiative heat transfer with artificial continuum cavity states in patterned hyperbolic metamaterials2017In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 95, no 24, article id 245405Article in journal (Refereed)
    Abstract [en]

    Localized cavity resonances due to nanostructures at material surfaces can greatly enhance radiative heat transfer (RHT) between two closely placed bodies owing to stretching of cavity states in momentum space beyond the light line. Based on such understanding, we numerically demonstrate the possibility of ultrabroadband super-Planckian RHT between two plates patterned with trapezoidal-shaped hyperbolic metamaterial (HMM) arrays. The phenomenon is rooted not only in HMM's high effective index for creating subwavelength resonators but also its extremely anisotropic isofrequency contour. The two properties enable one to create photonic bands with a high spectral density to populate a desired thermal radiation window. At submicron gap sizes between such two plates, the artificial continuum states extend outside the light cone, tremendously increasing overall RHT. Our study reveals that structured HMM offers unprecedented potential in achieving a controllable super-Planckian radiative heat transfer for thermal management at nanoscale.

  • 14.
    Dai, Jin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Ding, Fei
    Bozhevolnyi, Sergey I.
    Centre for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Ultrabroadband Super-Planckian Radiative Heat Transfer with Profile-Patterned Hyperbolic MetamaterialManuscript (preprint) (Other academic)
  • 15.
    Dai, Jin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Dyakov, S. A.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Radiative heat transfer between two dielectric-filled metal gratings2016In: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 93, no 15, article id 155403Article in journal (Refereed)
    Abstract [en]

    Nanoscale surface corrugation is known to be able to drastically enhance radiative heat transfer between two metal plates. Here we numerically calculate the radiative heat transfer between two dielectric-filled metal gratings at dissimilar temperatures based on a scattering approach. It is demonstrated that, compared to unfilled metal gratings, the heat flux for a fixed geometry can be further enhanced, by up to 650% for the geometry separated by a vacuum gap of g = 1 mu m and temperature values concerned in our study. The enhancement in radiative heat transfer is found to depend on refractive index of the filling dielectric, the specific grating temperatures, and naturally the gap size between the two gratings. The enhancement can be understood through examining the transmission factor spectra, especially the spectral locations of the spoof surface plasmon polariton modes. Of more practical importance, it's shown that the radiative heat flux can exceed that between two planar SiC plates with same thickness, separation, and temperature settings over a wide temperature range. This reaffirms that one can harness rich electromagnetic modal properties in nanostructured materials for efficient thermal management at nanoscale.

  • 16.
    Dai, Jin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dyakov, Sergey A.
    Bozhevolnyi, Sergey I.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Near-field radiative heat transfer between metasurfaces: A full-wave study based on two-dimensional grooved metal plates2016In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 94, no 12, article id 125431Article in journal (Refereed)
    Abstract [en]

    Metamaterials possess artificial bulk and surface electromagnetic states. Tamed dispersion properties of surface waves allow one to achieve a controllable super-Planckian radiative heat transfer (RHT) process between two closely spaced objects. We numerically demonstrate enhanced RHT between two two-dimensional grooved metal plates by a full-wave scattering approach. The enhancement originates from both transverse-magnetic spoof surface-plasmon polaritons and a series of transverse-electric bonding-and anti-bonding-waveguide modes at surfaces. The RHT spectrum is frequency selective and highly geometrically tailorable. Our simulation also reveals thermally excited nonresonant surface waves in constituent metallic materials may play a prevailing role for RHT at an extremely small separation between two metal plates, rendering metamaterial modes insignificant for the energy-transfer process.

  • 17.
    Dai, Jin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dyakov, Sergey A.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Enhanced near-field radiative heat transfer between corrugated metal plates: Role of spoof surface plasmon polaritons2015In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 92, no 3, article id 035419Article in journal (Refereed)
    Abstract [en]

    We demonstrate with the finite-difference time-domain method that radiative heat transfer between two parallel gold plates can be significantly enhanced by engraving periodic grooves with a subwavelength width on the plate surfaces. The enhancement increases with a decrease in the separation distance at near-field regime and it can be further efficiently improved by having a supercell with multiple grooves with different depths. We attribute this near-field enhancement to coupling of thermally excited spoof surface plasmon polaritons, a type of artificial surface wave inherent to structured metal surfaces [J. B. Pendry, L. Martin-Moreno, and F. J. Garcia-Vidal, Science 305, 847 (2004)]. The frequency-dependent contribution to the heat transfer, or transmission-factor spectrum, is confirmed by calculating the dispersion relation of guided modes by the two parallel corrugated plates through a finite-element method. Especially, the photonic density of states derived from the dispersion relation is found to have excellent agreement to the transmission-factor spectrum.

  • 18.
    Dai, Jin
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Ye, Fei
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Functional Materials, FNM (Closed 20120101).
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Functional Materials, FNM (Closed 20120101).
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Light absorber based on nano-spheres on a substrate reflector2013In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, no 6, p. 6697-6706Article in journal (Refereed)
    Abstract [en]

    We systematically study a type of plasmonic light absorber based on a monolayer of gold nano-spheres with less than 30 nm in diameters deposited on top of a continuous gold substrate. The influences of particle size, inter-particle distance, particle-substrate spacer size etc on the resonance are studied thoroughly with a 3D finite-element method. We identified that the high-absorption resonance is mainly due to gap plasmon (coupled through particle bodies) when the separation between neighboring nano-spheres is small enough, such as close to 1 nm; at larger particle separations, the resonance is dominated by particle dipoles (coupled through the host dielectric). Experimentally, an absorber was fabricated based on chemically-synthesized gold nanoparticles coated with silica shell. The absorber shows a characteristic absorption band around 810 nm with a maximum absorbance of approximately 90%, which agrees reasonably well with our numerical calculation. The fabrication technique can be easily adapted for devising efficient light absorbers of large areas.

  • 19.
    Dong, Hui
    et al.
    Nanyang Techbological University, Singapore.
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Gong, Yandong
    Yan, Min
    Nanyang Techbological University, Singapore.
    Zhou, Junqiang
    Wu, Chongqing
    Measurement of polarization mode dispersion vectors in optical fibers using a virtual Mueller matrix method2007In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 46, no 3, p. 035007-Article in journal (Refereed)
    Abstract [en]

    A virtual Mueller matrix method is proposed to measure the first- and second-order polarization mode dispersion (PMD) vectors in optical fibers. This method not only can use a large frequency step to attain low-noise PMD vector data, but also does not require knowledge of the input polarization states. Our measurement method has a simpler setup and is more accurate than the traditional Mueller matrix method.

  • 20.
    Dong, Hui
    et al.
    Nanyang Techbological University, Singapore.
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Gong, Yandong
    Yan, Min
    Nanyang Techbological University, Singapore.
    Zhou, Junqiang
    Wu, Chongqing
    Virtual generalized Mueller matrix method for measurement of complex polarization-mode dispersion vector in optical fibers2007In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 19, no 1, p. 27-29Article in journal (Refereed)
    Abstract [en]

    A virtual generalized Mueller matrix method (VGMMM) is proposed to measure the complex polarization-mode dispersion (PMD) vector in a fiber system with polarization-dependent loss or gain. VGMMM can attain the low-noise high-resolution PMD data using a relatively large frequency step, without the knowledge of input polarization states. VGMMM combines the advantages of both matrix-based methods and differentiation-based methods and overcomes their shortcomings. Experimental results on a fiber system confirm the validity and accuracy of VGMMM.

  • 21.
    Dong, Hui
    et al.
    Nanyang Techbological University, Singapore.
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Yan, Min
    Nanyang Techbological University, Singapore.
    Ning, Guoxiang
    Gong, Yandong
    Wu, Chongqing
    Generalized frequency dependence of output Stokes parameters in an optical fiber system with PMD and PDL/PDG2005In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 13, no 22, p. 8875-8881Article in journal (Refereed)
    Abstract [en]

    Dependence of output optical power, Stokes vector and degree of polarization on optical frequency is presented for an optical fiber system with both polarization mode dispersion and polarization-dependent loss or gain. The newly formulated equations are generalized for input light with arbitrary degree of polarization. The spectral resolved measurements of polarization mode dispersion using partially polarized light agree well with our theory.

  • 22.
    Dong, Hui
    et al.
    Nanyang Techbological University, Singapore.
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Yan, Min
    Nanyang Techbological University, Singapore.
    Zhou, Junqiang
    Ning, Guoxiang
    Gong, Yandong
    Wu, Chongqing
    Measurement of Mueller matrix for an optical fiber system with birefringence and polarization-dependent loss or gain2007In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 274, no 1, p. 116-113Article in journal (Refereed)
    Abstract [en]

    In an optical fiber system with both birefringence and polarization-dependent loss or gain (PDL/G), a set of input polarization states and their corresponding outputs are deduced to fulfill some general relationships in Stokes space, by considering the fact that the Mueller matrix of such an optical fiber system meets Lorentz transformation. Then, it can be proven that the minimum number of input polarization states is three for an explicit determination of such a Mueller matrix and no independent input parameter is redundant. Based on the theoretical findings, a general and simple approach is proposed to measure the Mueller matrix. The requirements regarding the choices of three inputs are presented for achieving optimum measurement stability and accuracy. Experimental results on an optical fiber system, formed by two 10-km long single-mode fibers with an optical isolator in between, show excellent agreement with the theory.

  • 23.
    Dong, Hui
    et al.
    Nanyang Techbological University, Singapore.
    Zhou, Junqiang
    Yan, Min
    Nanyang Techbological University, Singapore.
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Ma, Lin
    Gong, Yandong
    Wu, Chongqing
    Quasi-monochromatic fiber depolarizer and its application to polarization-dependent loss measurement2006In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 31, no 7, p. 876-878Article in journal (Refereed)
    Abstract [en]

    We theoretically derive the relationship between the degrees of polarization (DOPs) of input and output for an optical component with polarization-dependent loss (PDL) and birefringence. Based on the theoretical result, we propose a novel depolarizer for quasi-monochromatic light that can depolarize a fully polarized light with a 50 MHz linewidth to less than 0.2% in the DOR The depolarized light is then used to measure PDL in a single-mode optical fiber link. To the best of our knowledge, our new PDL measurement method is significantly faster than all known methods. Experimental results show excellent agreement with other methods.

  • 24.
    Dyakov, Sergey A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dai, Jin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, M.
    Thermal radiation dynamics in two parallel plates: The role of near field2014In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 90, no 4, p. 045414-Article in journal (Refereed)
    Abstract [en]

    The temperature dynamics of the radiative heat propagation in a multilayer structure is theoretically treated with a formalism combining the scattering matrix and Green's-functions methods. The time evolution of the temperature of parallel plates of silicon carbide in vacuum is simulated for different interplate distances and thicknesses of plates. The characteristic radiative heat exchange time and temperature of the plates at stationary state are determined from the time evolutions. The threshold interplate distance which separates heating and cooling regimes for the sink plate is found. We show that the variation of the interplate distance allows us to control the relaxation processes in the system of absorber and emitter.

  • 25.
    Dyakov, Sergey A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Dai, Jin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Near field thermal memory based on radiative phase bistability of VO22015In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 48, no 30, article id 305104Article in journal (Refereed)
    Abstract [en]

    We report the concept of a near-field memory device based on the radiative bistability effect in the system of two closely separated parallel plates of SiO2 and VO2 which exchange heat by thermal radiation in vacuum. We demonstrate that the VO2 plate, having metal-insulator transition at 340 K, has two thermodynamical steady-states. One can switch between the states using an external laser impulse. We show that due to near-field photon tunneling between the plates, the switching time is found to be only 5 ms which is several orders lower than in case of far field.

  • 26.
    Dyakov, Sergey A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Dai, Jin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Thermal self-oscillations in radiative heat exchange2015In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 106, no 6, article id 064103Article in journal (Refereed)
    Abstract [en]

    We report the effect of relaxation-type self-induced temperature oscillations in the system of two parallel plates of SiO2 and VO2 which exchange heat by thermal radiation in vacuum. The nonlinear feedback in the self-oscillating system is provided by metal-insulator transition in VO2. Using the method of fluctuational electrodynamics, we show that under the action of an external laser of a constant power, the temperature of VO2 plate oscillates around its phase transition value. The period and amplitude of oscillations depend on the geometry of the structure. We found that at 500 nm vacuum gap separating bulk SiO2 plate and 50 nm thick VO2 plate, the period of self-oscillations is 2 s and the amplitude is 4K, which is determined by phase switching at threshold temperatures of phase transition.

  • 27.
    Fu, Qiliang
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Yan, Min
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Jungstedt, Erik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Yang, Xuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Transparent plywood as a load-bearing and luminescent biocomposite2018In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 164, p. 296-303Article in journal (Refereed)
    Abstract [en]

    Transparent wood (TW) structures in research studies were either thin and highly anisotropic or thick and isotropic but weak. Here, transparent plywood (TPW) laminates are investigated as load-bearing biocomposites with tunable mechanical and optical performances. Structure-property relationships are analyzed. The plies of TPW were laminated with controlled fiber directions and predetermined stacking sequence in order to control the directional dependence of modulus and strength, which would give improved properties in the weakest direction. Also, the angular dependent light scattering intensities were investigated and showed more uniform distribution. Luminescent TPW was prepared by incorporation of quantum dots (QDs) for potential lighting applications. TPW can be designed for large-scale use where multiaxial load-bearing performance is combined with new optical functionalities.

  • 28. Gong, H.
    et al.
    Chen, Xi
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qu, Y.
    Li, Q.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, M.
    Photothermal Switching Based on Silicon Mach-Zehnder Interferometer Integrated with Light Absorber2016In: IEEE Photonics Journal, ISSN 1097-5764, E-ISSN 1943-0655, Vol. 8, no 2, article id 7456199Article in journal (Refereed)
    Abstract [en]

    We present an all-optical switch based on photothermal effects in a silicon Mach-Zehnder interferometer (MZI) integrated with a light absorber. The metal-insulator-metal light absorber located near the longer arm of the asymmetric MZI efficiently converts infrared light to heat. Pumped by a continuous-wave 1064-nm laser, the spectral transmittance of the fully etched strip waveguide (half-etched rib waveguide) MZI can be tuned with an efficiency of 38 pm/mW (98.5 pm/mW). Dynamic switching experiments show that the rise/fall time constant of the output probe light is 11.45/10.98 μs (8.25/7.13 μs) for the fully etched (half-etched) MZI.

  • 29. Gong, Hanmo
    et al.
    Yang, Yuanqing
    Chen, Xingxing
    Zhao, Ding
    Chen, Xi
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Li, Qiang
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Zhejiang University, Hangzhou, China.
    Gold nanoparticle transfer through photothermal effects in a metamaterial absorber by nanosecond laser2014In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 4, p. 6080-Article in journal (Refereed)
    Abstract [en]

    A non-complicated, controllable method of metallic nanoparticle fabrication at low operating light power is proposed. The method is based on laser-induced forward transfer, using a metamaterial absorber as the donor to significantly enhance the photothermal effect and reduce the operating light fluence to 35 mJ/cm(2), which is much lower than that in previous works. A large number of metallic nanoparticles can be transferred by one shot of focused nanosecond laser pulses. Transferred nanoparticles exhibit good size uniformity and the sizes are controllable. The optical properties of transferred particles are characterized by dark-field spectroscopy and the experimental results agree with the simulation results.

  • 30.
    Hao, Jiaming
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Wang, Jing
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Ultrathin wide-angle optical metamaterial absorber2010In: Optical Nanostructures for Photovoltaics (PV) 2010, 2010Conference paper (Refereed)
    Abstract [en]

    We present design, analysis, and experimental demonstration of an ultra-thin, wide-angle perfect metamaterial absorber at optical frequency. The absorption is tunable by adjusting the nanostructure dimensions and is almost independent of the incidence angle.

  • 31.
    Li, Qiang
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Song, Yi
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Efficient directional coupler based on plasmonic waveguide for photonic integrated circuits2010In: International Conference on Optical Communications and Networks 2010: 24-27 October 2010, Nanjing, China, 2010, no 574 CP, p. 366-368Conference paper (Refereed)
    Abstract [en]

    Two asymmetric directional couplers, including the dielectric-hybrid plasmonic coupler and the dielectric-metalinsulator-metal plasmonic coupler, are investigated. The proposed hybrid coupler features short coupling length, high coupling efficiency and can be integrated into the siliconbased platform. The applications of these hybrid couplers include the signal routing between plasmonic waveguides and dielectric waveguides in photonic integrated circuits and efficient excitation of plasmonic modes with conventional dielectric modes. Besides, a symmetric directional coupler based on silver nanowires is also demonstrated.

  • 32.
    Li, Qiang
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Wang, S.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Tong, L.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Silver nanowire based plasmon propagation, coupling and splitting at 1.55 μm wavelength2010In: 2010 Asia Communications and Photonics Conference and Exhibition, ACP 2010, 2010, p. 497-498Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate silver nanowire based plasmonic devices at optical communication wavelength 1.55 μm. The plasmon propagation loss in a 300 nm diameter silver nanowire is measured to be 0.3 dB/μm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nano-couplers and nano-splitters, are realized.

  • 33.
    Li, Qiang
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wang, Shanshan
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Tong, Limin
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Experimental Demonstration of Plasmon Propagation, Coupling, and Splitting in Silver Nanowire at 1550-nm Wavelength2011In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 17, no 4, p. 1107-1111Article in journal (Refereed)
    Abstract [en]

    We experimentally demonstrate silver-nanowire-based plasmonic devices including the nanowaveguide, the nanocoupler, and the nanosplitter at optical communication wavelength of 1550 nm. The plasmon propagation loss in a 300-nm diameter silver nanowire is measured to be 0.3 dB/mu m and the effective propagation length is 14.5 mu m. This loss is comparatively lower than that at 980 nm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nanocouplers, and nanosplitters, are realized. For the nanocoupler, the experimental results show that the plasmonic modes can be efficiently coupled between two closely positioned nanowires. While for the nanosplitter, the plasmonic mode is split with a power ratio of 2.6:1. These demonstrations experimentally prove the feasibility of extending the operating wavelength of silver-nanowire-based plasmonic devices to current optical communication wavelength with a lower loss, which are thus important steps for potentially utilizing low-loss nanowire-based plasmonic components for photonic integrated circuits.

  • 34.
    Li, Qiang
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wang, Shanshan
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Tong, Limin
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Silver nanowire based plasmon propagation, coupling and splitting at 1.55 mu m wavelength2011In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 7986Article in journal (Refereed)
    Abstract [en]

    We experimentally demonstrate silver nanowire based plasmonic devices at optical communication wavelength 1.55 mu m. The plasmon propagation loss in a 300 nm diameter silver nanowire is measured to be 0.3 dB/mu m. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nano-couplers and nano-splitters, are realized.

  • 35.
    Li, Qiang
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wang, Tao
    Su, Yikai
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Coupled mode theory analysis of mode-splitting in coupled cavity system2010In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 18, no 8, p. 8367-8382Article in journal (Refereed)
    Abstract [en]

    We analyze transmission characteristics of two coupled identical cavities, of either standing-wave (SW) or traveling-wave (TW) type, based on temporal coupled mode theory. Mode splitting is observed for both directly (cavity-cavity) and indirectly (cavity-waveguide-cavity) coupled cavity systems. The effects of direct and indirect couplings, if coexisting in one system, can offset each other such that no mode splitting occurs and the original single-cavity resonant frequency is retained. By tuning the configuration of the coupled cavity system, one can obtain different characteristics in transmission spectra, including splitting in transmission, zero transmission, Fano-type transmission, electromagnetically-induced-transparency (EIT)-like transmission, and electromagnetically-induced-absorption (EIA)-like transmission. It is also interesting to notice that a side-coupled SW cavity system performs similarly to an under-coupled TW cavity. The results are useful for the design of cavity-based devices for integration in nanophotonics.

  • 36.
    Li, Yuanyuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Fu, Qiliang
    Rojas, Ramiro
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Yan, Min
    KTH, School of Electrical Engineering (EES).
    Lawoko, Martin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Lignin-Retaining Transparent Wood2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 17, p. 3445-3451Article in journal (Refereed)
    Abstract [en]

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80wt% of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83%, haze of 75%, thermal conductivity of 0.23WmK(-1), and work-tofracture of 1.2MJm(-3) (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings.

  • 37.
    Li, Yuanyuan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Fu, Qiliang
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Yu, Shun
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance2016In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, no 4, p. 1358-1364Article in journal (Refereed)
    Abstract [en]

    Optically transparent wood (TW) with transmittance as high as 85% and haze of 71% was obtained using a delignified nanoporous wood template. The template was prepared by removing the light-absorbing lignin component, creating nanoporosity in the wood cell wall. Transparent wood was prepared by successful impregnation of lumen and the nanoscale cellulose fiber network in the cell wall with refractive-index-matched prepolymerized methyl methacrylate (MMA). During the process, the hierarchical wood structure was preserved. Optical properties of TW are tunable by changing the cellulose volume fraction. The synergy between wood and PMMA was observed for mechanical properties. Lightweight and strong transparent wood is a potential candidate for lightweight low-cost, light-transmitting buildings and transparent solar cell windows.

  • 38. Li, Yuanyuan
    et al.
    Yang, Xuan
    Fu, Qiliang
    Rojas, Ramiro
    Yan, Max
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Berglund, Lars
    Towards centimeter thick transparent wood through interface manipulation2018In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 3, p. 1094-1101Article in journal (Refereed)
    Abstract [en]

    Transparent wood is an attractive structural material for energy-saving buildings due to its high optical transmittance, good thermal insulation, and high toughness. However, thick highly transparent wood is challenging to realize. In the current work, highly transparent wood (1.5 mm) with a transmittance of 92%, close to that of pure PMMA (95%), is demonstrated. The high transmittance was realized by interface manipulation through acetylation of wood template. Both experiments and electromagnetic modeling support that the improved transmittance is mainly due to elimination of interface debonding gap. By applying this method, a centimeter-thick transparent wood structure was obtained. The transparent wood could be used as a substrate for an optically tunable window by laminating a polymer dispersed liquid crystal (PDLC) film on top. The techniques demonstrated are a step towards the replacement of glass in smart windows and smart buildings.

  • 39.
    Liu, Hairong
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Liu, Deming
    Yu, Xia
    Zhang, Ying
    Theoretical investigation on guiding IR light in hollow-core metallic fiber with corrugated inner surface2010In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 18, no 21, p. 21959-21964Article in journal (Refereed)
    Abstract [en]

    Hollow metallic fibers (HMFs) are in general lossy primarily owing to the fact that the guided transverse-magnetic (TM) light sustains a relatively high propagation loss. In this paper, we propose a type of practical hollow-core metallic fiber (HMF) with longitudinally corrugated inner surface for transmitting infrared (IR) light. Simulation results show that the loss of the fundamental TM mode can be easily reduced by 50 similar to 100 times compared to a HMF without surface corrugation. In contrast to the traditional HMF with a dielectric coating, it is shown that the loss of the fundamental TM mode in the proposed HMF is relatively insensitive to the corrugation layer thickness or equivalently the operating frequency.

  • 40.
    Liu, Hairong
    et al.
    Nanyang Techbological University, Singapore.
    Yan, Min
    Nanyang Techbological University, Singapore.
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Liu, Deming
    Design and analysis of anti-resonant reflecting photonic crystal VCSEL lasers2004In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 12, no 18, p. 4269-4274Article in journal (Refereed)
    Abstract [en]

    Anti-resonant reflecting photonic crystal structure is employed in vertical cavity surface emitting lasers (VCSELs) to achieve photon confinement in lateral direction. Such a design is promising in supporting large-aperture single-mode emission. In the configuration, hexagonal arrays of high-index cylinders which run vertically in the cladding region are introduced in the VCSEL's top DBR (p-DBR) mirror region. The transverse modal property of the proposed structure, especially leakage loss, has been theoretically investigated. An optimum design for the minimum radiation loss while maintaining single-mode operation has been discussed in this paper.

  • 41.
    Liu, Hairong
    et al.
    Optoelectronic Engineering Department, Huazhong University of Science and Technology.
    Yan, Min
    Network Technology Research Center, Nanyang Technological University, Singapore.
    Shum, Ping
    Nanyang Techbological University, Singapore.
    Zhang, Xinliang
    Liu, Deming
    Optimum design of anti-resonant reflecting photonic crystal vertical-cavity surface-emitting lasers2005In: Chinese Optics Letters, ISSN 1671-7694, Vol. 3, no SUPPL, p. S210-S212Article in journal (Refereed)
    Abstract [en]

    Anti-resonant reflecting photonic crystal structure in vertical-cavity surface-emitting lasers (VCSELs) to achieve photon confinement in lateral direction is introduced. This kind of design is proposed to support large aperture single-mode emission. A proper method to fabricate the proposed structure has also been discussed. Firstly a spacer layer will be fabricated between the active layer and pDBR layer. A hexagonal array of high-index cylinders will be designed by etching and re-growth on the spaced layer. The transverse modal property of the proposed structure has been investigated. An optimum design for the minimum radiation loss by considering of the cylinder diameter has been discussed in this paper.

  • 42.
    Lobov, Gleb S.
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Marinins, Aleksandrs
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Li, Jiantong
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Sugunan, Abhilash
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Thylen, Lars
    KTH, School of Biotechnology (BIO).
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Ostling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Size Impact of Ordered P3HT Nanofibers on Optical Anisotropy2016In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 217, no 9, p. 1089-1095Article in journal (Refereed)
    Abstract [en]

    Poly-3-hexylthiophene (P3HT) nanofibers are 1D crystalline structures with semiconductor properties. When P3HT nanofi bers are dispersed in nonconducting solvent, they react to external alternate electric field by aligning along the field lines. This can be used to create layers of ordered nanofi bers and is referred to as alternating current poling method. P3HT nanofi bers with three different size distributions are fabricated, using self-assembly mechanism in marginal solvents, and used for the alignment studies. Anisotropic absorption of oriented 2 mu m long nanofi bers exponentially increases with the magnitude of applied field to a certain asymptotic limit at 0.8 V mu m(-1), while 100-500 nm long nanofi bers respond to electric field negligibly. Effective optical birefringence of oriented 2 mu m long nanofi bers is calculated, based on the phase shift at 633 nm and the average layer thickness, to be 0.41. These results combined with further studies on real-time control over orientation of P3HT nanofi bers in liquid solution or host system are promising in terms of exploiting them in electroabsorptive and electrorefractive applications.

  • 43.
    Lobov, Gleb S.
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Marinins, Aleksandrs
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Li, Jiantong
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Sugunan, A.
    Thylén, Lars
    KTH, School of Biotechnology (BIO). Hewlett-Packard Laboratories, United States.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT).
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Electric field induced optical anisotropy of P3HT nanofibers in a liquid solution2015In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, no 11, p. 2642-2647Article in journal (Refereed)
    Abstract [en]

    The nanofiber morphology of regioregular Poly-3- hexylthiophene (P3HT) is a 1D crystalline structure organized by π - π stacking of the backbone chains. In this study, we report the impact of electric field on the orientation and optical properties of P3HT nanofibers dispersed in liquid solution. We demonstrate that alternating electric field aligns nanofibers, whereas static electric field forces them to migrate towards the cathode. The alignment of nanofibers introduces anisotropic optical properties, which can be dynamically manipulated until the solvent has evaporated. Time resolved spectroscopic measurements revealed that the electro-optical response time decreases significantly with the magnitude of applied electric field. Thus, for electric field 1.3 V ·μm-1 the response time was measured as low as 20 ms, while for 0.65 V ·μm-1 it was 110-150 ms. Observed phenomenon is the first mention of P3HT supramolecules associated with electrooptical effect. Proposed method provides real time control over the orientation of nanofibers, which is a starting point for a novel practical implementation. With further development P3HT nanofibers can be used individually as an anisotropic solution or as an active component in a guest-host system.

  • 44.
    Lobov, Gleb S.
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT).
    Marinins, Aleksandrs
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Li, Jiantong
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Sugunan, A.
    Thylen, Lars
    KTH, School of Biotechnology (BIO).
    Wosinski, L.ech
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Popov, Sergei Yu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Electro-optical response of P3HT nanofibers in liquid solution2015In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper (Refereed)
    Abstract [en]

    AC electric poling introduces in P3HT nanofibers anisotropic electro-optical response and birefringence. Along with birefringence, such material exhibits strong amplitude modulation which makes it more efficient alternative to liquid crystals. © 2015 OSA.

  • 45.
    Lobov, Gleb
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT).
    Marinins, Aleksandrs
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Li, Jiantong
    KTH, School of Information and Communication Technology (ICT).
    Sugunan, A.
    Thylén, Lars
    KTH, School of Biotechnology (BIO). Hewlett-Packard Laboratories, United States.
    Wosinski, L.ech
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Dynamic Manipulation of Optical Anisotropy of Suspended Poly-3-hexylthiophene Nanofibers2016In: Advanced Optical Materials, ISSN 2195-1071, Vol. 4, no 10, p. 1651-1656Article in journal (Refereed)
    Abstract [en]

    Poly-3-hexylthiophene (P3HT) nanofibers are 1D crystalline semiconducting nanostructures, which are known for their application in photovoltaics. Due to the internal arrangement, P3HT nanofibers possess optical anisotropy, which can be enhanced on a macroscale if nanofibers are aligned. Alternating electric field, applied to a solution with dispersed nanofibers, causes their alignment and serves as a method to produce solid layers with ordered nanofibers. The transmission ellipsometry measurements demonstrate the dichroic absorption and birefringence of ordered nanofibers in a wide spectral range of 400–1700 nm. Moreover, the length of nanofibers has a crucial impact on their degree of alignment. Using electric birefringence technique, it is shown that external electric field applied to the solution with P3HT nanofibers can cause direct birefringence modulation. Dynamic alignment of dispersed nanofibers changes the refractive index of the solution and, therefore, the polarization of transmitted light. A reversible reorientation of nanofibers is organized by using a quadrupole configuration of poling electrodes. With further development, the described method can be used in the area of active optical fiber components, lab-on-chip or sensors. It also reveals the potential of 1D conducting polymeric structures as objects whose highly anisotropic properties can be implemented in electro-optical applications.​

  • 46.
    Lou, Fei
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Whispering gallery mode nanodisk resonator based on layered metal-dielectric waveguide2014In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 22, no 7, p. 8490-8502Article in journal (Refereed)
    Abstract [en]

    This paper proposes a layered metal-dielectric waveguide consisting of a stack of alternating metal and dielectric films which enables an ultracompact mode confinement. The properties of whispering gallery modes supported by disk resonators based on such waveguides are investigated for achieving a large Purcell factor. We show that by stacking three layers of 10 nm thick silver with two layers of 50 nm dielectric layers (of refractive index n) in sequence, the disk radius can be as small as 61 nm similar to lambda(0) / (7n) and the mode volume is only 0.0175 (lambda(0) / (2n))(3). When operating at 40 K, the cavity's Q-factor can be similar to 670; Purcell factor can be as large as 2.3x10(4), which is more than five times larger than that achievable in a metal-dielectric-metal disk cavity in the same condition. When more dielectric layers with smaller thicknesses are used, even more compact confinement can be achieved. For example, the radius of a cavity consisting of seven dielectric-layer waveguide can be shrunk down to lambda(0) / (13.5n), corresponding to a mode volume of 0.005 lambda(0) / (2n))(3), and Purcell factor can be enhanced to 7.3x10(4) at 40 K. The influence of parameters like thicknesses of dielectric and metal films, cavity size, and number of dielectric layers is also comprehensively studied. The proposed waveguide and nanodisk cavity provide an alternative for ultracompact light confinement, and can find applications where a strong light-matter interaction is necessary.

  • 47. Mortensen, Niels Asger
    et al.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Sigmund, Ole
    Breinbjerg, Olav
    On the unambiguous determination of effective optical properties of periodic metamaterials: a one-dimensional case study2010In: JOURNAL OF THE EUROPEAN OPTICAL SOCIETY-RAPID PUBLICATIONS, ISSN 1990-2573, Vol. 5, p. 10010-Article in journal (Refereed)
    Abstract [en]

    We show how branch ambiguities in the extraction of effective parameters is arising as a direct consequence of the underlying Bloch state physics. The mutual importance of the different branches in general depends on the experimental context, and we show how the Fourier spectrum of the field inside the metamaterial can be used to access this. Different numerical examples illustrate how a predominant branch may be identified for lambda >> a while at higher frequency the power may be distributed over more branches. This is in particular true near band-edges and strong resonances. Extensions to two- and three-dimensional metamaterial designs are discussed.

  • 48.
    Neranon, Kitjanit
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Åslund, Mattias
    Draupner Innovations, Årsta, Sweden.
    Karalius, Antanas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Min
    Xu, Hao
    KTH, School of Engineering Sciences (SCI), Applied Physics. Department of Applied Physics, Science for Life Laboratory.
    Fu, Ying
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Petermann, Ingemar
    Nanoelectronics, Acreo Swedish ICT AB, Kista, Sweden.
    Björk, Per
    Nanoelectronics, Acreo Swedish ICT AB, Kista, Sweden.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Laser-induced, Surface Plasmon-enhanced Two-photon Excitation for Efficient Chemical Functionalization of Nanostructured Gold SurfacesManuscript (preprint) (Other academic)
  • 49. Ozturk, Z. Fatih
    et al.
    Xiao, Sanshui
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wubs, Martijn
    Jauho, Antti-Pekka
    Mortensen, N. Asger
    Field enhancement at metallic interfaces due to quantum confinement2011In: J NANOPHOTONICS, ISSN 1934-2608, Vol. 5, p. 051602-Article in journal (Refereed)
    Abstract [en]

    We point out an apparently overlooked consequence of the boundary conditions obeyed by the electric displacement vector at air-metal interfaces: the continuity of the normal component combined with the quantum mechanical penetration of the electron gas in the air implies the existence of a surface on which the dielectric function vanishes. This, in turn, leads to an enhancement of the normal component of the total electric field. We study this effect for a planar metal surface, with the inhomogeneous electron density accounted for by a Jellium model. We also illustrate the effect for equilateral triangular nanoislands via numerical solutions of the appropriate Maxwell equations, and show that the field enhancement is several orders of magnitude larger than what the conventional theory predicts.

  • 50.
    Qiu, Min
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Zhejiang University, China.
    Chen, Xi
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Shi, Yuechun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Gong, H.
    Zhao, D.
    Yang, Y.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Li, Q.
    Plasmonic enhanced photothermal effects and its applications2014Conference paper (Refereed)
    Abstract [en]

    We review here our recent studies on plasmonic enhanced photothermal effects in metallic nanostructure, and the applications of such effects. When light is shined on a prefect metamaterial absorber patterned with e-beam lithography, the gold nanoparticles (NPs) forming the absorber can be either transformed to nano-spherical-domes, or to truncated-octahedral shaped or multi-twined nanocrystals with large crystal grain sizes and flat boundary facets. The evolution of morphology and crystallinity of the gold NPs can be also observed. Evidences clearly show that the surface melting and the coalescence mechanism play a key role on nanocrystals formation. These melted gold nanospheres can even be transferred to another substrate, on which the transferred NPs exhibit excellent size uniformity. The strong photothermal effects can also be utilized to tune silicon photonics waveguides and resonators. It is shown that all-optical photothermal switching of Mach-Zehnder interferometers (MZI), silicon disk resonators, and silicon ring resonators is possible with the help of plasmonic nanoheaters. The switching response time and power consumption are all at reasonably low level.

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