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  • 1. Bach, Florian
    et al.
    Mero, Mark
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI), Physics.
    Zukauskas, Andrius
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Petrov, Valentin
    High repetition rate, femtosecond and picosecond laser induced damage thresholds of Rb:KTiOPO4 at 1.03 mu m2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 3, p. 744-750Article in journal (Refereed)
    Abstract [en]

    A laser-induced damage study is performed on blank, uncoated Rb:KTiOPO4 (RKTP) samples at 1.03 mu m with two different pulse durations of similar to 0.3 and similar to 1.0 ps and a repetition rate of 100 kHz. The effect of the sample temperature is also considered.

  • 2. Boyko, Andrey A.
    et al.
    Schunemann, Peter G.
    Guha, Shekhar
    Kostyukova, Nadezhda Y.
    Kolker, Dmitry B.
    Panyutin, Vladimir L.
    Marchev, Georgi M.
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Zukauskas, Andrius
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Mayorov, Fedor
    Petrov, Valentin
    Optical parametric oscillator pumped at similar to 1 mu m with intracavity mid-IR difference-frequency generation in OPGaAs2018In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 8, no 3, p. 549-554Article in journal (Refereed)
    Abstract [en]

    Intracavity difference-frequency generation (DFG) between signal and idler pulses is investigated in orientation-patterned GaAs inside the cavity of a similar to 1 mu m pumped nanosecond optical parametric oscillator (OPO). Using two different samples and temperature tuning in the non-critical configuration, tunability between 7 and 9.2 mu m is demonstrated. The superior thermo-mechanical properties of OPGaAs enabled also for the first time operation of this cascaded scheme at kilohertz (1-3 kHz) repetition rates reaching average powers similar to 10 mW in the mid-IR.

  • 3.
    Canalias, Carlota
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Mirov, Sergey
    Taira, Takunori
    Boulanger, Benoit
    Feature issue introduction: shaping and patterning crystals for optics2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 9, p. 3466-3470Article in journal (Other academic)
    Abstract [en]

    Shaping and patterning of bulk or thin layer crystals and ceramics are one of the new frontiers in the field of laser and nonlinear optics. These technical aspects are rarely published, but they are crucial for the fundamental studies as well as for technology and applications. This special issue features 15 articles that focus on the orienting, cutting, polishing, coating, bonding, writing guides, or poling crystals and ceramics for bulk- or micro-optics. We have here a corpus of contributions describing the techniques as well as the gain they bring in terms of functionality or performance of the fabricated components devoted to optics and photonics. (C) 2017 Optical Society of America

  • 4.
    Coetzee, Riaan Stuart
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Duzellier, Sophie
    Dherbecourt, Jean-Baptiste
    Zukauskas, Andrius
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Raybaut, Myriam
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Gamma irradiation-induced absorption in single-domain and periodically-poled KTiOPO4 and Rb:KTiOPO42017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 11, p. 4138-4146Article in journal (Refereed)
    Abstract [en]

    We investigate the effect of gamma radiation on flux grown KTiOPO4 and Rb:KTiOPO4 samples, as well as their periodically poled variants. Specifically, we study the altered transmission due to color-center formation via gamma irradiation. We measured the transmission of our samples for varying radiation doses and demonstrate effective temperature annealing of gamma radiation induced color centers. We measured a maximum transmission difference of 2% in our samples, which was easily corrected with temperature annealing. No long term and permanent changes were found to be induced in our samples.

  • 5.
    Coetzee, Riaan Stuart
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Thilmann, Nicky
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Zukauskas, Andrius
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Nanosecond laser induced damage thresholds in KTiOPO4 and Rb:KTiOPO4 at 1 µm and 2 µm2015In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, no 9, p. 2090-2095Article in journal (Refereed)
    Abstract [en]

    Optimum design of high-energy cascaded parametric down-conversion schemes from 1 μm requires accurate knowledge of the laser induced damage threshold (LIDT) of the nonlinear crystal employed. We report surface LIDT measurements in KTiOPO4 (KTP) and Rb:KTP (RKTP) with nanosecond pulses at 1.064 μm and 2.1 μm. LIDT results for nanosecond pulses at 2 μm for KTP and RKTP have not been previously reported to the best of our knowledge.

  • 6.
    De Luca, Eleonora
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Sanatinia, Reza
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Srinivasan, Anand
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Focused ion beam milling of gallium phosphide nanostructures for photonic applications2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 2, p. 587-596Article in journal (Refereed)
    Abstract [en]

    We report on the fabrication of gallium phosphide (GaP) nanowaveguides of controlled dimensions, as small as 0.03 μm and aspect ratio in excess of 20, using focused ion beam (FIB) milling. A known limitation of this fabrication process for photonic applications is the formation of gallium droplets on the surface. We demonstrate a post-fabrication step using a pulsed laser to locally oxidize the excess surface gallium on the FIB milled nanostructures. The process significantly reduces the waveguide losses. The surface optical quality of the fabricated GaP nanowaveguides has been evaluated by second-harmonic generation experiments. Surface and bulk contributions to second-order optical nonlinearities have been identified by polarization measurements. The presented method can potentially be applied to other III-V nanostructures to reduce optical losses.

  • 7.
    Dev Choudhury, Bikash
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Abedin, Ahmad
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Dev, Apurba
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Sanatinia, Reza
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Silicon micro-structure and ZnO nanowire hierarchical assortments for light management2013In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 3, no 8, p. 1039-1048Article in journal (Refereed)
    Abstract [en]

    We present fabrication and optical characterization of Si microstructure-ZnO nanowire (NWs) hierarchical structures for light management. Random and periodic hierarchical structures constituting Si micro pillar or micro pyramid arrays with overgrown ZnO NWs have been fabricated. Inexpensive colloidal lithography in combination with dry and wet chemical etching is used to fabricate Si microstructures, and ZnO NWs are grown by hydrothermal synthesis. The periodic Si micro pyramid-ZnO NWs hierarchical structure shows broadband antireflection with average reflectance as low as 2.5% in the 300-1000 nm wavelength range. A tenfold enhancement in Raman intensity is observed in this structure compared to planar Si sample. These hierarchical structures with enriched optical properties and high surface to volume ratio are promising for photovoltaic (PV) and sensor applications.

  • 8.
    Dev Choudhury, Bikash
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Casquel, R.
    Banuls, M. J.
    Sanza, F. J.
    Laguna, M. F.
    Holgado, M.
    Puchades, R.
    Maquieira, A.
    Barrios, C. A.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Silicon nanopillar arrays with SiO2 overlayer for biosensing application2014In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 4, no 7, p. 1345-1354Article in journal (Refereed)
    Abstract [en]

    We present the fabrication of silicon dioxide (SiO2) coated silicon nanopillar array structures and demonstrate their application as sensitive optical biosensors. Colloidal lithography, plasma dry etching and deposition processes are used to fabricate SiO2 coated Si nanopillar arrays with two different diameters and periods. Proof of concept bio recognition experiments are carried out with the bovine serum albumin (BSA)/antiBSA model system using Fourier transform visible and IR spectrometry (FT-VIS-IR) in reflection mode. A limit of detection (LoD) value of 5.2 ng/ml is estimated taking in to account the wavenumber uncertainty in the measurements.

  • 9.
    Fokine, Michael
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Theodosiou, Antreas
    Song, Seunghan
    Hawkins, Thomas
    Ballato, John
    Kalli, Kyriacos
    Gibson, Ursula J.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Laser structuring, stress modification and Bragg grating inscription in silicon-core glass fibers2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 5, p. 1589-1597Article in journal (Refereed)
    Abstract [en]

    Semiconductor core fibers have numerous potential applications in optoelectronics and photonics, and the key to realizing these opportunities is controlled processing of the material. We present results on laser treatments for manipulating the core structure as well as the glass cladding. More specifically, using quasi-CW 10.6 mu m radiation, the clad glass can be softened and the core can be controllably melted. This is shown to permit tapering, localized formation of optical resonators, and stress modification of the as-drawn fiber and structures within it. Shown for the first time to the authors' knowledge are Bragg gratings written by modification of the silicon/glass interface using fs laser illumination at 517 nm. The cores of these fibers show stress alterations, with indications of quasi-periodic stress relief in the glass.

  • 10. Forsberg, Pontus
    et al.
    Malmström, Mikael
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. Uppsala Univ, Sweden.
    Catalan, Ernesto Vargas
    Karlsson, Mikael
    Diamond grating waveplates2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 6, p. 2024-2030Article in journal (Refereed)
    Abstract [en]

    Two designs of diamond quarter-wave plates for CO2 lasers, based on the birefringence of sub-wavelength gratings, were manufactured and tested. In one design the grating was etched on the surface of a 300 mu m thick polycrystalline diamond substrate. The other consisted of a diamond grating hanging freely in air, suspended at the edges from a silicon frame. The free-hanging design, while more fragile, had several advantages both in terms of fabrication and performance such as a larger grating period, higher transmission, and no need for an antireflective treatment of the backside.

  • 11. Franz, Yohann
    et al.
    Ren, Haonan
    Healy, Noel
    Ignatyev, K
    Jones, Maxwell
    Hawkins, Thomas
    Ballate, John
    Gibson, Ursula
    Norwegian Univ of Science and Technol..
    Peacock, Anna
    Material properties of tapered crystalline silicon core fibers2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 6, p. 2055-2061Article in journal (Refereed)
    Abstract [en]

    Crystalline silicon optical fibers are emerging as a promising platform for a wide range of optoelectronic applications. Here we report a crystallographic study of the material properties within silicon fibers that have been post-processed via a tapering procedure to obtain small, few micron-sized core diameters. Our results reveal that the tapering process can improve the polysilicon quality of the core through the formation of large, centimeter long crystal grains, thus significantly reducing the optical losses.

  • 12. Gerasimov, V. S.
    et al.
    Ershov, A. E.
    Karpov, S. V.
    Gavrilyuk, A. P.
    Zakomirnyi, Vadim I.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Rasskazov, I. L.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Polyutov, S. P.
    Thermal effects in systems of colloidal plasmonic nanoparticles in high-intensity pulsed laser fields [Invited]: publisher's note (vol 7,pg 555, 2017)2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 3, p. 799-799Article in journal (Refereed)
  • 13. Gerasimov, V. S.
    et al.
    Ershov, A. E.
    Karpov, S. V.
    Gavrilyuk, A. P.
    Zakomirnyi, Vadim
    KTH. Siberian Federal University, Russian Federation.
    Rasskazov, I. L.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Polyutov, S. P.
    Thermal effects in systems of colloidal plasmonic nanoparticles in high-intensity pulsed laser fields [Invited]2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 2, p. 555-568Article in journal (Refereed)
    Abstract [en]

    We have studied light induced processes in nanocolloids and composite materials containing ordered and disordered aggregates of plasmonic nanoparticles accompanied by their strong heating. A universal comprehensive physical model that combines mechanical, electrodynamical, and thermal interactions at nanoscale has been developed as a tool for investigations. This model was used to gain deep insight on phenomena that take place in nanoparticle aggregates under high-intensity pulsed laser radiation resulting in the suppression of nanoparticle resonant properties. Verification of the model was carried out with single colloidal Au and Ag nanoparticles and their aggregates.

  • 14.
    Guo, Wenhua
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Holmberg, Patrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Fokine, Michael
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Fabrication of long-period fiber gratings through periodic ablation using a focused CO2-laser beam2015In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, no 11, p. 2702-2714Article in journal (Refereed)
    Abstract [en]

    Fabrication of long period gratings in optical fibers through periodic ablation using a focused CO2 laser beam has been studied. During the thermal ablation process most of the energy is absorbed at the glass surface, due to the high extinction coefficient of silica at the laser wavelength, resulting in rapid increase in temperature. Subsequent heat dissipation occurs through vaporization and ejection of molten material, heat conduction axially along the fiber, radiation and through convection. The high surface temperatures involved during ablation can result in a significant increase in temperature of the fiber itself, causing unwanted off-resonance background losses during grating fabrication. In order to minimize losses the temperature needs to be sufficiently low to avoid micro-bending and core deformation, triggered by the decrease in viscosity, while at the same time enabling strong grating formation through laser induced modification of the glass. In this work we have used short-period fiber Bragg gratings in order to assess the temperature dynamics within the fiber during ablation. Using a single grating written into the core, positioned below the point of ablation, we measure the peak temperature within the core of the fiber. When ablation was performed between two gratings, forming a short Fabry-Perot cavity, a different and faster response was recorded, which we ascribe to thermally induced stress and strain caused by the thermal expansion of the surface during ablation. By identifying suitable processing parameters we successfully fabricate strong long-period gratings with background losses of 0.5 dB to 1 dB when periodically ablating the fiber with up to 50 pulses. Experimental results indicate that the maximum core temperatures during ablation under these conditions are limited to within 600 degrees C to 1000 degrees C.

  • 15.
    Junesand, Carl
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Kataria, Himanshu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Metaferia, Wondwosen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Julian, Nick
    Wang, Zhechao
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA. Ghent University, Dept. of Information Technology, Sint-Pietersnieuwstraat 41, 9000 Ghent, Belgium .
    Sun, Yan-Ting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Bowers, John
    Pozina, Galia
    Hultman, Lars
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Study of planar defect filtering in InP grown on Si by epitaxial lateral overgrowth2013In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 3, no 11, p. 1960-1973Article in journal (Refereed)
    Abstract [en]

    InP thin films have been grown on InP/Si substrate by epitaxial lateral overgrowth (ELOG). The nature, origin and filtering of extended defects in ELOG layers grown from single and double openings in SiO2 mask have been investigated. Whereas ELOG layers grown from double openings occasionally exhibit threading dislocations (TDs) at certain points of coalescence, TDs are completely absent in ELOG from single openings. Furthermore, stacking faults (SFs) observed in ELOG layers grown from both opening types originate not from coalescence, but possibly from formation during early stages of ELOG or simply propagate from the seed layer through the mask openings. A model describing their propagation is devised and applied to the existent conditions, showing that SFs can effectively be filtered under certain conditions. ELOG layers grown from identical patterns on InP substrate contained no defects, indicating that the defect-forming mechanism is in any case not inherent to ELOG itself.

  • 16. Kou, Pengfei
    et al.
    Yang, Liu
    Chi, Kequn
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. Zhejiang University, China.
    Large-area and uniform transparent electrodes fabricated by polymethylmethacrylate-assisted spin-coating of silver nanowires on rigid and flexible substrates2015In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, no 10, p. 2347-2358Article in journal (Refereed)
    Abstract [en]

    We have proposed a full-solution polymethylmethacrylate (PMMA)-assisted spin-coating method for uniformly distributing silver nanowires, which are carried in PMMA, on both rigid and flexible substrates as transparent electrodes. High optical transmittance (similar to 0.91, much better than that of a 80 nm thick ITO that is typically applied to solar cells), good electrical conductivity (similar to 15 Omega/sq on average, comparable to that of ITO) and long-term stability have been demonstrated for the devices on 4 '' glass substrates, which are also better than the devices fabricated without the assistance of PMMA. The mechanism is presented through systematic investigation of the effects of two key processing parameters, i.e., the volume ratio of the Ag NWs in ethanol to the PMMA, and the second rotary speed of the spin-coating process. This method has been extended to flexible substrates. Good uniformity is also achieved over a large area of 5 cm x 5 cm. A simple application demonstration indicates again the great potential of our method for mass production of Ag NW networks, which are likely to replace ITO as transparent electrodes.

  • 17. Li, Nana
    et al.
    Wen, Xuanyuan
    Liu, Jing
    Wang, Baoju
    Zhan, Qiuqiang
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Yb3+-enhanced UCNP@SiO2 nanocomposites for consecutive imaging, photothermal-controlled drug delivery and cancer therapy2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 4, p. 1161-1171Article in journal (Refereed)
    Abstract [en]

    UCNP-based drug delivery systems commonly rely on stimulisensitive auxiliaries, lacking a straightforward manipulation strategy. Here we designed Yb3+-enhanced upconversion/ mesoporous silica nanocomposites (UCNP@SiO2) for consecutive cell imaging, photothermal drug delivery and cancer therapy. Core UCNPs (NaYbF4: 2% Er3+) were synthesized and coated with mesoporous silica, whose high-efficiency photothermal properties were verified in vitro. Then doxorubicin hydrochloride (DOX) was loaded on the UCNP@SiO2 and successfully triggered to release by a 975 nm laser of 150 mW or 300 mW. Before the therapy, we used a much lower laser power of 15 mW (which would cause little DOX release) for UCNP-probed fluorescence imaging of Hela cells and affirmed a favorable cell uptake of nanocomposites. Subsequently, cell viability assay and PI stain have demonstrated that the 300 mW laser could manipulate drug delivery of UCNP@SiO2-DOX and cause a severe loss of cell viability. The Yb3+-enhanced UCNP@SiO2 shows a great potential in simultaneous biomedical imaging and photothermal-triggered on-site drug delivery for chemotherapy of cancer. (C) 2016 Optical Society of America

  • 18. Liu, Jing
    et al.
    Li, Nana
    Wu, Ruitao
    Zhao, Yuxiang
    Zhan, Qiuqiang
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. SCNU, S China Acad Adv Optoelect, SCNU ZJU Joint Res Ctr Photon, Guangzhou 510006, Guangdong, Peoples R China.
    Sub-5-nm lanthanide-doped ZrO2@NaYF4 nanodots as efficient upconverting probes for rapid scanning microscopy and aptamer-mediated bioimaging2015In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, no 8, p. 1759-1771Article in journal (Refereed)
    Abstract [en]

    Upconversion nanoparticles (UCNPs) is a class of promising probes widely used in protein molecules imaging due to the no photobleaching and non-blinking emission. However, it is still remained challenging to synthesize a type of ultra-small but bright UCNPs. In this paper, a new class of efficient sub-5-nm upconversion nanodots (UCNDs) was elaborately designed and experimentally demonstrated. The proposed uniform UCNDs comprise two parts: a 3.5-nm Ln(3+)-doped ZrO2 core and 0.5-nm NaYF4 shell. The emission intensity of the proposed UCNDs was measured to be more than 10 times brighter than that of the conventional 10-nm NaYF4 UCNPs. Under 300 kW.cm(-2) irradiance excitation, the 15 mol% Er3+-doped UCNDs exhibit an 18-fold enhanced intensity and one fifth emission lifetime compared to the 0.5 mol% Er3+-doped ones. Using the biocompatible UCNDs, the aptamer-mediated proteins-targeted imaging was performed and demonstrated high efficiency. These ultra-small, efficient UCNDs would have great potentials in rapid scanning and cellular imaging.

  • 19. Liu, Qingkun
    et al.
    Wang, Nan
    Chen, Pengxin
    Zhang, Yuan
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zhejiang University, Hangzhou 310058, China .
    Large-area bulk self-assembly of plasmonic nanorods in nematic liquid crystal via surface-mediated alignment2013In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 3, no 11, p. 1918-1924Article in journal (Refereed)
    Abstract [en]

    In this paper, we introduce a novel method to organize gold nanorods (GNRs) on a large scale by means of nematic lyotropic liquid crystal (LC) and surface-induced bulk alignment. LC is unidirectionally aligned via surface-treatment, and then gets GNRs organized with a negative order parameter in bulk through elastic force. The self-assembled GNRs (with a considerable high concentration of about 6 wt%) in LC exhibit a strong polarization-dependent localized surface plasmon resonance (LSPR). Polarized optical microscopic imaging, polarization-dependent extinction and scattering spectra of LSPR are utilized to characterize the spatial orientation of GNRs. This method is compatible with the state-of-the-art LC display technique and allows for large-scale fabrication of optical metamaterials, plasmonic polarizers comprised of self-aligned anisometric nanoparticles with extremely low cost.

  • 20.
    Lobov, G. S.
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Marinins, A.
    KTH, School of Information and Communication Technology (ICT).
    Etcheverry, S.
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT).
    Vasileva, Elena
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Sugunan, A.
    Laurell, F.
    Thylén, Lars
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Wosinski, L.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT).
    Toprak, M. S.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Direct birefringence and transmission modulation via dynamic alignment of P3HT nanofibers in an advanced opto-fluidic component2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 1, p. 52-61Article in journal (Refereed)
    Abstract [en]

    Poly-3-hexylthiophene (P3HT) nanofibers are semiconducting high-aspect ratio nanostructures with anisotropic absorption and birefringence properties found at different regions of the optical spectrum. In addition, P3HT nanofibers possess an ability to be aligned by an external electric field, while being dispersed in a liquid. In this manuscript we show that such collective ordering of nanofibers, similar to liquid crystal material, significantly changes the properties of transmitted light. With a specially fabricated opto-fluidic component, we monitored the phase and transmission modulation of light propagating through the solution of P3HT nanofibers, being placed in the electric field with strength up to 0.1 V/μm. This report describes a technique for light modulation, which can be implemented in optical fiber-based devices or on-chip integrated components.

  • 21.
    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.

  • 22.
    Loiko, Pavel
    et al.
    ITMO Univ, Kronverkskiy Pr 49, St Petersburg 197101, Russia..
    Maria Serres, Josep
    URV, Dept Quim Fis & Inorgan, Fis & Cristal Lografia Mat & Nanomat FiCMA FiCNA, EMaS, E-43007 Tarragona, Spain..
    Delekta, Szymon Sollami
    KTH, School of Information and Communication Technology (ICT).
    Kifle, Esrom
    URV, Dept Quim Fis & Inorgan, Fis & Cristal Lografia Mat & Nanomat FiCMA FiCNA, EMaS, E-43007 Tarragona, Spain..
    Boguslawski, Jakub
    Wroclaw Univ Sci & Technol, Fac Elect, Laser & Fiber Elect Grp, Wybrzeze S Wyspianskiego 27, PL-50370 Wroclaw, Poland.;Polish Acad Sci, Inst Phys Chem, Kasprzaka 44-52, PL-01224 Warsaw, Poland..
    Kowalczyk, Maciej
    Wroclaw Univ Sci & Technol, Fac Elect, Laser & Fiber Elect Grp, Wybrzeze S Wyspianskiego 27, PL-50370 Wroclaw, Poland..
    Sotor, Jaroslaw
    Wroclaw Univ Sci & Technol, Fac Elect, Laser & Fiber Elect Grp, Wybrzeze S Wyspianskiego 27, PL-50370 Wroclaw, Poland..
    Aguilo, Magdalena
    URV, Dept Quim Fis & Inorgan, Fis & Cristal Lografia Mat & Nanomat FiCMA FiCNA, EMaS, E-43007 Tarragona, Spain..
    Diaz, Francesc
    URV, Dept Quim Fis & Inorgan, Fis & Cristal Lografia Mat & Nanomat FiCMA FiCNA, EMaS, E-43007 Tarragona, Spain..
    Griebner, Uwe
    Max Born Inst Nonlinear Opt & Short Pulse Spect, Max Born Str 2a, D-12489 Berlin, Germany..
    Petrov, Valentin
    Max Born Inst Nonlinear Opt & Short Pulse Spect, Max Born Str 2a, D-12489 Berlin, Germany..
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT).
    Li, Jiantong
    KTH, School of Information and Communication Technology (ICT).
    Mateos, Xavier
    URV, Dept Quim Fis & Inorgan, Fis & Cristal Lografia Mat & Nanomat FiCMA FiCNA, EMaS, E-43007 Tarragona, Spain..
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT).
    Inkjet-printing of graphene saturable absorbers for similar to 2 mu m bulk and waveguide lasers2018In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 8, no 9, p. 2803-2814Article in journal (Refereed)
    Abstract [en]

    A technique for inkjet-printing of graphene saturable absorbers (SAs) for similar to 2-mu m bulk and waveguide lasers is presented. Based on distillation-assisted solvent exchange to fabricate high-concentration graphene inks, this technique is capable of producing few-layer graphene films of arbitrary shape. Absorption saturation of graphene printed on glass is demonstrated at similar to 1.56 mu m for picosecond and femtosecond pulses indicating a large fraction of the saturable losses. Inkjet-printed transmission-type graphene SAs are applied in passively Q-switched nanosecond thulium (Tm) microchip and planar waveguide lasers. The Tm microchip laser generates 136 ns / 1.2 mu J pulses at 1917 nm with a repetition rate of 0.37 MHz with a Q-switching conversion efficiency reaching 65%. The planar waveguide laser generates 98 ns / 21 nJ pulses at 1834 nm at a repetition rate in the MHz-range. The inkjet-printing technique is promising for production of patterned SAs for waveguide lasers.

  • 23.
    Maglione, Mario
    et al.
    University of Bordeaux.
    Theerthan, Anand
    University of Bordeaux.
    Rodriguez, Vincent
    University of Bordeaux.
    Peña, Alexandra
    university of Grenoble Alpes.
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Ménaert, Bertrand
    university of Grenoble Alpes.
    Boulanger, Benoît
    university of Grenoble Alpes.
    Intrinsic ionic screening of the ferroelectric polarization of KTP revealed by second-harmonic generation microscopy2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 1, p. 137-145Article in journal (Refereed)
    Abstract [en]

    Mobile charges and lattice polarization interact in ferroelectric materials because of the Coulomb interaction between the mobile free charges and the fixed lattice dipoles. Using SHG microscopy, we have investigated this mutual screening in KTiOPO4, a ferroelectric/superionic single crystal in which the mobile charges are K$+$ ions. The ionic accumulation close to the crystal surfaces leads to orders of magnitude increase of SHG. This ionic space charge model is supported by the absence of such an effect in non-ionic conductor but ferroelectric BaTiO3, by its temperature dependence in KTiOPO4 and by its broad depletion at domain walls.

  • 24.
    Malmstrom, Mikael
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Karlsson, Mikael
    Forsberg, Pontus
    Cai, Yixiao
    Nikolajeff, Fredrik
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Waveguides in polycrystalline diamond for mid-IR sensing2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 4, p. 1286-1295Article in journal (Refereed)
    Abstract [en]

    8 mm long channel waveguides were manufactured in polycrystalline diamond with inductively coupled plasma etching and characterized in terms of mode-profile and propagation loss in the 1.5 - 3.4 mu m spectral region. As proof of principle, the waveguides were evaluated in an evanescent field sensing setup targeting the CH absorption peak of isopropanol at similar to 3.4 mu m, showing good agreement with numerical finite element simulations. (C) 2016 Optical Society of America

  • 25.
    Manzo, Michele
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Gallo, Katia
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Two-dimensional domain engineering in LiNbO3 via a hybrid patterning technique2011In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 1, no 3, p. 365-371Article in journal (Refereed)
    Abstract [en]

    We propose a novel electric field poling technique for the fabrication of nonlinear photonic crystals in congruent LiNbO3 substrates, based on a hybrid bi-dimensional mask, which combines periodic proton-exchange and electrode patterns. With it we demonstrate rectangular bulk lattices with a periodicity of 8 µm x 6.78 µm in 500 µm-thick substrates.

  • 26.
    Mensi, Mounir
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Becerra, D. L.
    Ivanov, Ruslan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Marcinkevičius, Saulius
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Nakamura, S.
    Denbaars, S. P.
    Speck, J. S.
    Properties of near-field photoluminescence in green emitting single and multiple semipolar (2021) plane InGaN/GaN quantum wells2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 1, p. 39-45Article in journal (Refereed)
    Abstract [en]

    Scanning near-field photoluminescence (PL) spectroscopy has been applied to green emitting (2021) plane InGaN/GaN quantum well (QW) structures with 1, 5 and 10 wells to reveal the influence of the number of QWS on PL properties and their spatial variation. The data show no additional broadening or shift of the PL spectra related to the increase of the number of QWs. The QWs in the multiple QW structures are found to be nearly identical and the well width and/or alloy composition fluctuations uncorrelated. In spite that the thickness of the 10 QW structure is over the critical, no PL changes related to a structural relaxation have been detected.

  • 27. Polyakov, S. M.
    et al.
    Karhu, E.
    Zamiri, R.
    Moisset, C.
    Iliopoulos, K.
    Vullum, P. E.
    Österberg, Ulf L.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. Norwegian University of Science and Technology (NTNU), Norway.
    Gibson, Ursula Jane
    KTH, School of Engineering Sciences (SCI), Applied Physics. Norwegian University of Science and Technology (NTNU), .
    Nonlinear optical response and structural properties of MBE-grown Fe:ZnS films2018In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 8, no 2, p. 356-367Article in journal (Refereed)
    Abstract [en]

    Fe-doped ZnS films of high optical quality were fabricated using vacuum vapor deposition. Preferential crystalline orientation and phase purity of the host ZnS films were increased by the addition of small amounts of Fe, and the spectral shape of the 2-4 μm absorption peak is maintained up to the highest concentration tested (9 at.%). However, Raman shifts of the Fe:ZnS films indicate the inclusion of disordered material at high Fe concentrations, and below-gap optical Kerr effect measurements show an increase in χ(3) correlated with this data. Nonlinear optical properties of the films were also measured using the Z-scan method at 532 nm, and saturable absorption of the Fe-based intraband levels at 2.94 μm was confirmed.

  • 28.
    Song, S.
    et al.
    Norwegian Univ Sci & Technol, Dept Phys & Porelabs, N-7491 Trondheim, Norway..
    Healy, N.
    Newcastle Univ, Emerging Technol & Mat Grp, Newcastle NE1 7RU, England..
    Svendsen, S. K.
    Norwegian Univ Sci & Technol, Dept Phys & Porelabs, N-7491 Trondheim, Norway..
    Osterberg, U. L.
    Norwegian Univ Sci & Technol NTNU, Dept Elect Syst, N-7491 Trondheim, Norway..
    Covian, A. V. Cuervo
    Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA..
    Liu, J.
    Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 USA..
    Peacock, A. C.
    Univ Southampton, Optoelect Res Ctr, Southampton SO17 1BJ, Hants, England..
    Ballato, J.
    Clemson Univ, Dept Mat Sci & Engn, Clemson, SC 29634 USA..
    Laurell, F.
    KTH Royal Inst Technol, Dept Appl Phys, S-10044 Stockholm, Sweden..
    Fokine, Michael
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Gibson, Ursula J.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Norwegian Univ Sci & Technol, Dept Phys & Porelabs, N-7491 Trondheim, Norway..
    Crystalline GaSb-core optical fibers with room-temperature photoluminescence2018In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 8, no 6, p. 1435-1440Article in journal (Refereed)
    Abstract [en]

    Glass-clad, GaSb-core fibers were drawn and subsequently laser annealed. The as-drawn fibers were found to be polycrystalline, possess Sb inclusions, and have oxide contamination concentrations of less than 3 at%. Melting and resolidifying regions in the cores using 10.6 mu m CO2 laser radiation yielded single crystalline zones with enhanced photoluminescence (PL), including the first observation of strong room temperature PL from a crystalline core fiber. Annealed fibers show low values of tensile strain and a bandgap close to that of bulk GaSb. 

  • 29.
    Tjörnhammar, Staffan
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Meastroni, Valerio
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics. Politecnico di Milano.
    Zukauskas, Andrius
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Uždavinys, Tomas Kristijonas
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Infrared absorption in KTP isomorphs induced with blue picosecond pulses2015In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, no 12, p. 2951-2963, article id 249512Article in journal (Refereed)
  • 30. Tolstik, Nikolai
    et al.
    Sorokin, Evgeni
    Karhu, Eric A.
    Gorbachenya, Konstantin
    Polyakov, Stanislav M.
    Kisel, Viktor E.
    Kuleshov, Nikolai
    Furtula, Vedran
    Gibson, Ursula J.
    KTH, School of Engineering Sciences (SCI), Applied Physics. NTNU - Norwegian University of Science and Technology, Norway.
    Sorokina, Irina T.
    Spectral-luminescent properties of vapor deposited Cr:ZnS thin films and their application as saturable absorbers for 1.5-mu m erbium lasers2018In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 8, no 3, p. 522-531Article in journal (Refereed)
    Abstract [en]

    We report the results of the extensive spectral-luminescent characterization including concentration quenching analysis of the first laser-quality vapor-deposited Cr:ZnS films, and demonstrate their use as saturable absorbers. Comparison of spectral-luminescent properties with bulk Cr: ZnS indicates their high laser quality, opening the way towards industrial mid-IR thin-disk and waveguide lasers. Successful implementation of the grown films in a Q-switched Er, Yb:GdAB solid-state laser emitting at 1.52 mu m gives clear experimental evidence of the high quality of the films.

  • 31.
    Uždavinys, Tomas Kristijonas
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Becerra, D. L.
    Ivanov, Ruslan
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Denbaars, S. P.
    Nakamura, S.
    Speck, J. S.
    Marcinkevicius, Saulius
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Influence of well width fluctuations on recombination properties in semipolar InGaN quantum wells studied by time- and spatially-resolved near-field photoluminescence2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 9, article id 3116Article in journal (Refereed)
    Abstract [en]

    Scanning near-field photoluminescence spectroscopy has been applied to distinguish the relevance of quantum well (QW) alloy composition and well width fluctuations on emission linewidth and recombination times in semipolar (2021) plane InGaN QWs. It has been found that well width fluctuations, compared to variations of InGaN alloy composition, play a negligible role in defining the photoluminescence linewidth. However, the well width strongly affects the recombination times. Prolonged radiative and nonradiative carrier lifetimes in wide QWs have been attributed to electron and hole separation by in-plane electric fields caused by nonplanarity of QW interfaces.

  • 32. Wang, Nan
    et al.
    Evans, Julian S.
    Liu, Qingkun
    Wang, Shaowei
    Khoo, Iam-Choon
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. Zhejiang University, China.
    Electrically controllable self-assembly for radial alignment of gold nanorods in liquid crystal droplets2015In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, no 5, p. 1065-1070Article in journal (Refereed)
    Abstract [en]

    We demonstrate the dispersion and alignment of gold nanorods in 5CB liquid crystal droplets in silicon oil with a radial director structure. This biphasic system shows that the nanorods are stabilized against phase boundary driven aggregation. The radial alignment of the droplets can be further controlled by electric field. This method is potentially useful for the fabrication of hybrid nanostructured materials, such as plasmonic polymer dispersed liquid crystals and self-assembly-based devices; it could also be extended for use with magnetic, semi-conducting, or up-conversion nanoparticles.

  • 33. Yong, Y. -S
    et al.
    Aravazhi, S.
    Vázquez-Córdova, S. A.
    Carvajal, J. J.
    Díaz, F.
    Herek, J. L.
    García-Blanco, S. M.
    Pollnau, Markus
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. University of Twente, Netherlands.
    Direct confocal lifetime measurements on rare-earth-doped media exhibiting radiation trapping2017In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, no 2, p. 527-532Article in journal (Refereed)
    Abstract [en]

    Radiation trapping occurs in rare-earth-doped active media with strong spectral overlap of luminescence and ground-state absorption. It is demonstrated experimentally that a confocal measurement mitigates the influence of radiation trapping on the measured luminescence lifetime, hence allowing for direct extraction of the lifetime from the measured decay curves. The radiation trapping effect is largely suppressed by probing a small sample volume and rejecting the photons reemitted from the unpumped region. This non-destructive measurement method is applied to ytterbium (Yb3+) activated potassium double tungstate crystalline layers with Yb3+ concentrations ranging from 1.2 at.% up to 76 at.% (~8 × 1019 - 5 × 1021 cm-3). The measured lifetime values are comparable to the results reported for Yb3+-doped potassium double tungstate powder diluted in liquid.

  • 34. Zhan, Qiuqiang
    et al.
    Wang, Baoju
    Wen, Xuanyuan
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Controlling the excitation of upconverting luminescence for biomedical theranostics: neodymium sensitizing2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 4, p. 1011-1023Article in journal (Refereed)
    Abstract [en]

    With the rapid development of nanotechnology over the past decade, lanthanide doped upconverting nanoparticles (UCNPs) have been successfully synthesized and have emerged as an important class of nanomaterials. In contrast to the traditional Yb3+-sensitized UCNPs, the emerging Nd3+-sensitized UCNPs have many merits in controlling the excitation of upconverting luminescence, including minimizing overheating effect, increasing the imaging depth and so on. In this review paper, we provide a comprehensive survey of the most recent advances in developing Nd3+-sensitized UCNPs, which include nanocomposition, mechanisms, and some typical nanostructures of Nd3+-sensitized UCNPs. Furthermore, an important emphasis is placed on various applications including downconversion and upconversion photoluminescence for bioimaging, high-resolution, and deep tissue imaging and tumor diagnosis and therapy. Potential challenges and prospective development are also discussed. (C) 2016 Optical Society of America

  • 35.
    Zukauskas, Andrius
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Pasiskevicius, Valdas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Laurell, Fredrik
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    High-fidelity periodic domain structures in KTiOAsO4 for the visible spectral range2013In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 3, no 9, p. 1444-1449Article in journal (Refereed)
    Abstract [en]

    We demonstrate room temperature periodic poling of KTiOAsO4 crystals with a period of 8.49 mu m for second harmonic generation of 1066 nm wavelength. The crystals are tested in a continuous wave SHG setup at 533 nm and show high quality periodic ferroelectric domain structure across the whole 1 mm crystal thickness, exhibiting d(eff) = 10.5 pm/V and normalized conversion efficiency of 1.2%/Wcm.

1 - 35 of 35
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