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  • 151.
    Cederström, Björn
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Lundqvist, Mats
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ribbing, Carolina
    Uppsala Universitet.
    Multi-prism x-ray lens2002Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 81, nr 8, s. 1399-1401Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Refractive x-ray lenses with a triangular surface profile have been used to focus a synchrotron beam to sub-mum line width. These lenses are free from spherical aberration and work in analogy with one-dimensional focusing parabolic compound refractive lenses. However, the focal length can be easily varied by changing the gap between the two jaws. Silicon lenses were fabricated by wet anisotropic etching, and epoxy replicas were molded from the silicon masters. The lenses provided intensity gains up to a factor of 32 and the smallest focal line width was 0.87 mum. The simplified geometry and associated fabrication technique open possibilities for low-Z materials such as beryllium, which should greatly enhance the performance of refractive x-ray optics. (C) 2002 American Institute of Physics.

  • 152.
    Cederström, Björn
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ribbing, C.
    Lundqvist, M.
    Generalized prism-array lenses for hard X-rays2005Ingår i: Journal of Synchrotron Radiation, ISSN 0909-0495, E-ISSN 1600-5775, Vol. 12, s. 340-344Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A Fresnel-like X-ray lens can be constructed by a triangular array of identical prisms whose base corresponds to the 2 pi-shift length. Each column of prisms is progressively shifted from the optical axis by an arbitrary fraction of the prism height. Similarly to the multi-prism lens, quasi-parabolic profiles are formed by a superposition of straight-line segments. The resulting projected lens profile is approximately linear with a Fresnel-lens pattern superimposed on it to provide the focusing. This geometry exhibits a significantly larger effective aperture than conventional parabolic refractive lenses. Prototype lenses were fabricated by deep reactive ion etching of silicon. These one-dimensionally focusing lenses were tested at a synchrotron beamline and provided focal line-widths down to 1.4 mu m FWHM and an intensity gain of 39 at a photon energy of 13.4 keV. Fabrication imperfections gave rise to unwanted interference effects resulting in several intensity maxima in the focal plane. The presented design allows the focal length to be shortened without decreasing the feature size of the lens. Furthermore, this feature size does not limit the resolution as for real Fresnel optics.

  • 153. Cen, Min
    et al.
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab). South China Normal University, China.
    Moeyaert, Veronique
    Megret, Patrice
    Wuilpart, Marc
    Full monitoring for long-reach TWDM passive optical networks2016Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 24, nr 14, s. 15782-15797Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a novel and simple fiber monitoring system based on multi-wavelength transmission-reflection analysis for long-reach time and wavelength division multiplexing passive optical networks. For the first time, the full localization functionality of long-reach passive optical networks is possible with the proposed monitoring scheme, including supporting fault detection, identification, and localization in both feeder and distribution fiber segments. By measuring the transmitted and reflected/backscattered optical powers launched by an unmodulated continuous-wave optical source, the proposed solution is able to supervise the network with good spatial accuracy, a high detection speed and a low impact on data traffic. Both the theoretical analysis and experimental validation show that the proposed scheme is capable of providing an accurate fault monitoring functionality for long-reach time and wavelength division multiplexing passive optical networks.

  • 154. Chacinski, M.
    et al.
    Chitica, N.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Transmission of 40 Gb/s over 55 m multimode fiber using 12 GHz bandwidth system based on vertical-cavity surface-emitting laser2014Ingår i: Asia Communications and Photonics Conference, ACP, 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Error free transmission (E-12) over 55 m long standard MMF at 40 Gb/s data rate is demonstrated with moderate signal conditioning on the VCSEL. The VCSEL has a-3 dBe bandwidth of 15 GHz resulting in system bandwidth of 12GHz, giving 3.3 bit/s/Hz coding efficiency.

  • 155.
    Chacinski, Marek
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Dynamic Characterization of Semiconductor Lasers and Intensity Modulators2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The research work presented in this thesis deals with characterization ofdynamics of active photonic devices that are based on semiconductormaterials. The thesis contains an introduction and a collection of publishedarticles in peer reviewed international journals and conferences.The introduction starts with the physical background and a review of thesemiconductor material properties which both affects the design andfabrication of the devices and determine their performance in applicationssuch as wavelength, optical power and attenuation, drive current andvoltage, temperature sensitivity and modulation bandwidth.The next chapter of the introduction is dedicated to various kinds ofsemiconductor lasers. It describes the physical principles, steady stateoperation and the dynamical response. The laser is essentially an opticalcavity consisting of a material with optical gain inbetween two reflectivemirrors. Special attention is given to the spectral shape of the mirrorreflectivity and its effect on the laser dynamics and how these effects canbe distinguished from those of the gain material.In order to improve dynamic performance, it is common that the laser,instead of being directly modulated by varying the drive current, isconnected to a separate modulator. The next chapter is therefore devotedto electroabsorption modulators for high speed intensity modulation andtheir integration to lasers. In order to fully take advantage of the highintrinsic modulation bandwidth of these devices it is important to havea good microwave design to avoid electrical parasitics. A segmented paddesign to achieve this is briefly described.The last part of the introduction covers measurements techniques that wereimplemented to experimentally investigate above devices. A description ofthe measurement methods, including practical hints and methods forevaluation of the measured results are provided.

  • 156.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Berggren, Jesper
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Kjebon, Olle
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Hammar, Mattias
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sundgren, Petrus
    Marcks von Würtemberg, Rikard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    1.3 um InGaAs VCSELs: Influence of the Large Gain-Cavity Detuning on the Modulation and Static Performance2004Ingår i: Proc. of 30th European Conference on Optical Communication 2004, 2004Konferensbidrag (Refereegranskat)
  • 157.
    Chacinski, Marek G.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Isaksson, Mats
    Kjebon, Olle
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Wang, Qin
    Effects of detuned loading on the modulation performance of widely tunable MG-Y lasers2008Ingår i: Semiconductor Lasers And Laser Dynamics III / [ed] Panajotov, KP; Sciamanna, M; Valle, AA; Michalzik, R, 2008, Vol. 6997, s. 99709-99709Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Detuning Loading Effect, i.e., the effects of the modulation performance on the position of the lasing mode relative to the Bragg reflection peak, is investigated in a Modulated Grating Y-branch laser. By proper adjustment of the lasing mode position, simultaneous chirp reduction and modulation bandwidth enhancement can be obtained. The lasing mode position is also crucial for side mode suppression ratio and output power.

  • 158.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Isaksson, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Schatz, Johan Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    High-speed direct Modulation of widely tunable MG-Y laser2005Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 17, nr 6, s. 1157-1159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic performance of the modulated-grating Y-branch laser is presented. In order to reach over 40-nm tuning range, the devices utilize an additive Vernier effect and relative tuning of two reflecting gratings. The device shows high (> 13 dBrn ex-facet) and uniform (< 1.2-dB variation) steady state output power over the tuning range, and sidemode suppression ratio > d40 dB. The laser behavior under small- and large-signal operation conditions is investigated. The laser exhibits a resonance frequency of 7.4-8.8 GHz at 80-mA bias. A 10-Gb/s eye diagram measurement showed, high extinction ratio and signal-to-noise ratio.

  • 159.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Isaksson, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    D'Oosterlinck, W.
    Morthier, G.
    Widely Tunable Wavelength Conversion 10 Gb/s Using a Modulated Grating Y-branch Laser Integrated with an Optical Amplifier2007Ingår i: OFC/NFOEC 2007 - Optical Fiber Communication and the National Fiber Optic Engineers Conference 2007, 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    A simple integrated tunable wavelength converter is presented. 10 Gb/s XGM conversion of signals at wavelength 1530-1560 nm to 1531-1556 nm and transmission at 2.5 Gb/s over 25 km SSMF of the converted signals were achieved.

  • 160.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Impact of losses in the Bragg section on the dynamics of detuned loaded DBR lasers2010Ingår i: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 46, nr 9, s. 1360-1367Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamics of a distributed Bragg reflector laser with optical losses in the Bragg section is studied in detail. It is found that the modulation response depends not only on the detuning of the lasing wavelength from the Bragg reflectivity peak but also on the magnitude of the waveguide losses in the Bragg section. Depending on the losses, the damping of the relaxation peak can either increase or decrease when the laser is detuned on the long wavelength flank of the Bragg peak. Hence, in order to achieve maximum modulation bandwidth of the laser, the laser needs not only to have the correct detuning but also an optimized waveguide loss in the Bragg section. The physical reason for this dependence is discussed in terms of a modified rate equation model.

  • 161.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Kjebon, Olle
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Hammar, Mattias
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Marcks von Würtemberg, Rickard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Mogg, Sebastian
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Sundgren, Petrus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Berggren, Jesper
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Single-mode 1.27 μm InGaAs vertical cavity surface-emitting lasers with temperature-tolerant modulation characteristics2005Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, nr 21, s. 211109-1-211109-3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic performance of InGaAs/GaAs 1.27 &mu; m single-mode vertical cavity surface emitting lasers (VCSELs) is presented. In order to reach such a long wavelength, the devices utilize highly strained double-quantum wells and a large detuning between the material gain peak and cavity resonance. It is found that the large detuning improves the temperature stability of both static and modulation characteristics. A resonance frequency of 7.8-9.5 GHz and optical power of 0.30 mW in fiber was maintained throughout the investigated temperature range of 20-90 &DEG; C. The intrinsic response of the device suggests that long-wavelength InGaAs/GaAs VCSELs have the potential to be used as low cost uncooled optical transmitters at 10 Gbit/s. &COPY; 2005 American Institute of Physics. &COPY; 2005 American Institute of Physics.

  • 162.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Berggren, Jesper
    Yu, X.
    KTH.
    Marcks Von Würtemberg, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Hammar, Mattias
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Dynamic properties of electrically p-n confined, epitaxially regrown 1.27 μm InGaAs single-mode vertical-cavity surface-emitting lasers2009Ingår i: IET optoelectronics, ISSN 1751-8768, Vol. 3, nr 3, s. 163-167Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic performance including chirp measurements of 1.27 mu m single-mode InGaAs/GaAs vertical-cavity surface-emitting lasers (VCSELs) with a large gain-cavity offset is presented. The VCSELs are based on a novel p-n confinement structure with selective area epitaxial regrowth. A resonance frequency of 9.11 GHz, a slope efficiency of 0.25 W/A and an alpha-factor of 5.7 were measured. The modulation bandwidth is limited by electrical parasitics. Eye diagrams at 5 Gb/s with 7 dB extinction ratio and Q-factor around 5 were obtained. The results are compared with the performance of oxide-confined VCSELs with similar active layer and negative gain-cavity detuning.

  • 163.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Scholes, A.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Ericsson, P.
    Isaksson, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Hammerfeldt, S.
    Silicon optical bench for flip-chip integration of high speed widely tunable lasers2008Ingår i: Second International Conference On Advanced Optoelectronics And Lasers / [ed] Sukhoivanov, IA; Svich, VA; Shmaliy, YS, 2008, Vol. 7009, s. 904-904Konferensbidrag (Refereegranskat)
    Abstract [en]

    A silicon optical bench for flip chip mounted widely tunable modulated-grating Y-branch lasers is presented. Its impact on the static and dynamic performance of the laser device is evaluated and compared with a conventional aluminum nitride carrier. The carriers exhibited similar thermal and static performance but the dynamic performance was limited by the electrode layout and the higher microwave losses of the silicon optical bench. With improved microwave design of the electrodes, flip-chip mounting on a silicon optical bench is promising for low cost assembly of high-speed multi-electrode devices

  • 164.
    Chacinski, Marek
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Stoltz, Björn
    Syntune AB, Kista, Sweden.
    Hammerfeldt, Stefan
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Monolithically Integrated 100 GHz DFB-TWEAM2009Ingår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 7, nr 16, s. 3410-3415Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A monolithically integrated distributed feedback (DFB) laser and traveling-wave electro-absorption modulator (TWEAM) with >= 100 GHz -dBe bandwidth suitable for Non-return-to-zero (NRZ) operation with on-off keying (OOK) is presented. The steady-state, small-signal modulation response, microwave reflection, chirp characteristic, and both data operation and transmission were investigated. The DFB-TWEAM was found to be an attractive candidate for future short distance communication in high bitrates systems.

  • 165. Chacinski, Marek
    et al.
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Willén, Bo
    Stoltz, Björn
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101).
    Electroabsorption Modulators Suitable for 100-Gb/s Ethernet2008Ingår i: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 29, nr 9, s. 1014-1016Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The design of a traveling-wave electroabsorption modulator (TWEAM) has been improved to decrease the drive voltage. The absorption layer was optimized and together with a novel segmentation of microwave design was introduced to increase the active modulator length. The resulting -3-dBe bandwidth of fabricated devices was estimated to be 99 GHz. Extinction ratios of 10 dB back-to-back and 6.7 dB after transmission over 2.2-km long fiber were measured with an incident drive voltage of only 2 V peak to peak. This TWEAM performance is believed to constitute a new state of the art for modulators suitable for 100-Gb/s Ethernet with on-off keying.

  • 166. Chang, Lantian
    et al.
    Dijkstra, Meindert
    Ismail, Nur
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Pollnau, Markus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    de Ridder, Rene M.
    Worhoff, Kerstin
    Subramaniam, Vinod
    Kanger, Johannes S.
    Waveguide-coupled micro-ball lens array suitable for mass fabrication2015Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 23, nr 17, s. 22414-22423Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate a fabrication procedure for the direct integration of micro-ball lenses on planar integrated optical channel waveguide chips with the aim to reduce the divergence of light that arises from the waveguide in both horizontal and vertical directions. Fabrication of the lenses is based on photoresist reflow which is a procedure that allows for the use of photolithography for careful alignment of the lenses with respect to the waveguides and enables mass production. We present in detail the design and fabrication procedures. Optical characterization of the fabricated micro-ball lenses demonstrates a good performance in terms of beam-size reduction and beam shape. The beam half divergence angle of 1544 nm light is reduced from 12.4 degrees to 1.85 degrees.

  • 167.
    Chang, Zhongwen
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Reaktorfysik.
    Modelling of Dislocation Bias in FCC Materials2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Irradiation induced void swelling is problematic for the application of austenitic steels under high dose irradiation. In this thesis, the swelling is characterized by dislocation bias. The dislocation bias is obtained using the finite element method, accounting for fcc copper and nickel under electron irradiation. The methodology is implemented with the interaction energies between an edge dislocation and point defects. Analytically derived interaction energies, which are based on elasticity theory, are compared with interaction energies obtained from atomistic model using semi-empirical atomic potentials as physics basis. The comparison shows that the description of analytical interaction energies is inaccurate in the dislocation core regions. The bias factor dependence on dislocation density and temperature is presented and discussed. At high temperatures or low dislocation densities, the two approaches tend to converge. However, the dislocation bias based on the interaction energies from the two approaches, reveals larger discrepancy for nickel than for copper. The impact on dislocation bias from the different stacking fault energies of copper and nickel is elaborated. Nickel, which has a larger stacking fault energy, is predicted to have larger swelling rate than copper under the same irradiation conditions.

  • 168.
    Chang, Zhongwen
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Reaktorfysik.
    Olsson, Pär
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Reaktorfysik.
    Sandberg, Nils
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Reaktorfysik.
    Terentyev, Dmitry
    Interaction Energy Calculations of Edge Dislocation with Point Defects in FCC Cu2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    In order to improve the dislocation bias (DB) model of swelling under irradiation, a large scale of atomistic simulation of the interaction in face centered cubic (FCC) Cu model lattice between an edge dislocation (ED) and point defects such as a vacancy, a self-interstital atom (SIA) have been performed for various configurations. It is found dislocation core splits into partial cores after energy relaxation. Interactions with any SIA conficurations is one order of magnitute larger than with a vacancy. The reason that SIA creats a larger dilatation volumn than the vacancy is directly observed from calculation. Furthurmore, within the interaction range, an octahedron position rather than dumbbell in <100> direction is observed in the stable state after relaxation in interactions between a edge dislocation and a dumbbell SIA. Comparision of interaction energy in analytical and atomistic calculation shows that analytical one has a stronger interaction in vacancy-ED systems, suggesting that the bias factor (BF) from analytical calculation is larger than from atomistic calculation.

  • 169.
    Chang, Zhongwen
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Reaktorfysik.
    Olsson, Pär
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Reaktorfysik.
    Terentyev, Dmitry
    Sandberg, Nils
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Reaktorfysik.
    Dislocation bias factors in fcc copper derived from atomistic calculations2013Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 441, nr 1-3, s. 357-363Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Atomistic calculations were employed in order to calculate the interaction energy of an edge dislocation with different point defects. The bias factor was calculated by applying a finite element method on the interaction energy landscapes obtained from the atomistic calculations. A comparison of the calculated bias factor with a model based on elasticity theory reveals around 30% discrepancy under conditions representative for electron irradiation at 600 degrees C. Possible reasons are discussed. The bias factor dependence on dislocation density and ambient temperature is presented and discussed.

  • 170. Chapman, I. T.
    et al.
    Graves, J. P.
    Sauter, O.
    Zucca, C.
    Asunta, O.
    Buttery, R. J.
    Coda, S.
    Goodman, T.
    Igochine, V.
    Johnson, Thomas
    KTH, Skolan för elektro- och systemteknik (EES), Fusionsplasmafysik.
    Jucker, M.
    La Haye, R. J.
    Lennholm, M.
    Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER2013Ingår i: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 53, nr 6, s. 066001-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    13MW of electron cyclotron current drive (ECCD) power deposited inside the q = 1 surface is likely to reduce the sawtooth period in ITER baseline scenario below the level empirically predicted to trigger neoclassical tearing modes (NTMs). However, since the ECCD control scheme is solely predicated upon changing the local magnetic shear, it is prudent to plan to use a complementary scheme which directly decreases the potential energy of the kink mode in order to reduce the sawtooth period. In the event that the natural sawtooth period is longer than expected, due to enhanced a particle stabilization for instance, this ancillary sawtooth control can be provided from >10MW of ion cyclotron resonance heating (ICRH) power with a resonance just inside the q = 1 surface. Both ECCD and ICRH control schemes would benefit greatly from active feedback of the deposition with respect to the rational surface. If the q = 1 surface can be maintained closer to the magnetic axis, the efficacy of ECCD and ICRH schemes significantly increases, the negative effect on the fusion gain is reduced, and off-axis negative-ion neutral beam injection (NNBI) can also be considered for sawtooth control. Consequently, schemes to reduce the q = 1 radius are highly desirable, such as early heating to delay the current penetration and, of course, active sawtooth destabilization to mediate small frequent sawteeth and retain a small q = 1 radius. Finally, there remains a residual risk that the ECCD + ICRH control actuators cannot keep the sawtooth period below the threshold for triggering NTMs (since this is derived only from empirical scaling and the control modelling has numerous caveats). If this is the case, a secondary control scheme of sawtooth stabilization via ECCD + ICRH + NNBI, interspersed with deliberate triggering of a crash through auxiliary power reduction and simultaneous pre-emptive NTM control by off-axis ECCD has been considered, permitting long transient periods with high fusion gain. The power requirements for the necessary degree of sawtooth control using either destabilization or stabilization schemes are expected to be within the specification of anticipated ICRH and ECRH heating in ITER, provided the requisite power can be dedicated to sawtooth control.

  • 171.
    Chen, Daru
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Qin, Shan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Yu, Zhangwei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Tunable and injection-switchable erbium-doped fiber laser of line structure2007Ingår i: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 49, nr 4, s. 765-768Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A tunable and injection-switchable erbium-doped fiber (EDF) laser is proposed based on a line structure formed by a fiber Sagnac loop reflector and an fiber Bragg grating (FBG). Wavelength switching is achieved by controlling the power of the tunable injection laser. The self-seeded wavelength corresponding to the Bragg wavelength of the FBG can be tuned by, for example, heating the FBG, and the injection wavelength can be tuned over a wide range of about 50 nm. The characteristics of the wavelength switching for different levels of the EDF pump power and different wavelengths of the injection laser are studied experimentally. The present fiber laser has the advantages of tunability, stability, low amplified spontaneous emission noise, and high injection efficiency when compared with a fiber ring laser. Rapid wavelength switching is expected and the transient switching response of the laser is also studied.

  • 172. Chen, G.
    et al.
    Damasco, J.
    Qiu, H.
    Shao, W.
    Ohulchanskyy, T. Y.
    Valiev, Rashid
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. Tomsk State University,Tomsk, Russian Federation.
    Wu, X.
    Han, G.
    Wang, Y.
    Yang, C.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Prasad, P. N.
    Energy-Cascaded Upconversion in an Organic Dye-Sensitized Core/Shell Fluoride Nanocrystal2015Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 15, nr 11, s. 7400-7407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lanthanide-doped upconversion nanoparticles hold promises for bioimaging, solar cells, and volumetric displays. However, their emission brightness and excitation wavelength range are limited by the weak and narrowband absorption of lanthanide ions. Here, we introduce a concept of multistep cascade energy transfer, from broadly infrared-harvesting organic dyes to sensitizer ions in the shell of an epitaxially designed core/shell inorganic nanostructure, with a sequential nonradiative energy transfer to upconverting ion pairs in the core. We show that this concept, when implemented in a core-shell architecture with suppressed surface-related luminescence quenching, yields multiphoton (three-, four-, and five-photon) upconversion quantum efficiency as high as 19% (upconversion energy conversion efficiency of 9.3%, upconversion quantum yield of 4.8%), which is about ∼100 times higher than typically reported efficiency of upconversion at 800 nm in lanthanide-based nanostructures, along with a broad spectral range (over 150 nm) of infrared excitation and a large absorption cross-section of 1.47 × 10-14 cm2 per single nanoparticle. These features enable unprecedented three-photon upconversion (visible by naked eye as blue light) of an incoherent infrared light excitation with a power density comparable to that of solar irradiation at the Earth surface, having implications for broad applications of these organic-inorganic core/shell nanostructures with energy-cascaded upconversion.

  • 173. Chen, Rui-Pin
    et al.
    Chew, Khian-Hooi
    Zhou, Guoquan
    Dai, Chao-Qing
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. Zhejiang University, China.
    Vectorial effect of hybrid polarization states on the collapse dynamics of a structured optical field2016Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 24, nr 24, s. 28143-28153Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The collapse dynamics of a structured optical field with a distribution of spatially-variant states of polarization (SoP) and a spiral phase in the field cross section is studied using the two-dimensional coupled nonlinear Schrodinger equations. The self-focusing of a structured optical field with an inhomogeneous SoP distribution can give rise to new phenomena of collapse dynamics that is completely different from a scalar field. The collapse patterns are closely related to the topological charges of the vortexas well as the polarization, the initial power, and the SoP distribution in the field cross section. A single on-axis collapse or multiple off-axis partial collapses may occur due to the self-focusing effects of linearly, elliptically and circularly polarized components located at different positions of the field cross-section. The polarization in the core of the collapsing beam is always linearly polarized. The structured collapsing beams, which are driven by the vortex, propagate along a spiral trajectory in a saturated medium.

  • 174. Chen, S
    et al.
    Svedendahl, M
    Käll, M
    Gunnarsson, L
    Dmitriev, A
    Ultrahigh sensitivity made simple: nanoplasmonic label-free biosensing with an extremely low limit-of-detection for bacterial and cancer diagnostics.2009Ingår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 20, nr 43Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a simple and robust scheme for biosensing with an ultralow limit-of-detection down to several pg cm(-2) (or several tens of attomoles cm(-2)) based on optical label-free biodetection with localized surface plasmon resonances. The scheme utilizes cost-effective optical components and comprises a white light source, a properly functionalized sensor surface enclosed in a simple fluidics chip, and a spectral analyzer. The sensor surface is produced by a bottom-up nanofabrication technique with hole mask colloidal lithography. Despite its simplicity, the method is able to reliably detect protein-protein binding events at low picomolar and femtomolar concentrations, which is exemplified by the label-free detection of the extracellular adherence protein (EAP) found on the outer surface of the bacterium Staphylococcus aureus and of prostate-specific antigen (PSA), which is believed to be a prostate cancer marker. These experiments pave the way towards an ultra-sensitive yet compact biodetection platform for point-of-care diagnostics applications.

  • 175. Chen, Si
    et al.
    Jokilaakso, Nima
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Björk, Per
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Zhang, Shi-Li
    A two-terminal silicon nanoribbon field-effect pH sensor2010Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 97, nr 26, s. 264102-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports on a two-terminal silicon nanoribbon (SiNR) field-effect pH sensor operated in electrolyte. Observed experimentally and confirmed by modeling, the sensor is activated by self-gating with a gate bias set by the potential difference of the two terminals. The effect of this gate bias on the SiNR conductance is modulated by the potential drop over the electrical double layer (EDL) established on the SiNR surface, similarly to the threshold voltage modulation by EDL in a three-terminal SiNR field-effect transistor with an independent gate electrode. The potential drop over EDL is determined by the pH value of the electrolyte.

  • 176. Chen, Si
    et al.
    Svedendahl, Mikael
    Antosiewicz, Tomasz J
    Käll, Mikael
    Plasmon-enhanced enzyme-linked immunosorbent assay on large arrays of individual particles made by electron beam lithography.2013Ingår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, nr 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultrasensitive biosensing is one of the main driving forces behind the dynamic research field of plasmonics. We have previously demonstrated that the sensitivity of single nanoparticle plasmon spectroscopy can be greatly enhanced by enzymatic amplification of the refractive index footprint of individual protein molecules, so-called plasmon-enhanced enzyme-linked immunosorbent assay (ELISA). The technique, which is based on generation of an optically dense precipitate catalyzed by horseradish peroxidase at the metal surface, allowed for colorimetric analysis of ultralow molecular surface coverages with a limit of detection approaching the single molecule limit. However, the plasmonic response induced by a single enzyme can be expected to vary for a number of reasons, including inhomogeneous broadening of the sensing properties of individual particles, variation in electric field enhancement over the surface of a single particle and variation in size and morphology of the enzymatic precipitate. In this report, we discuss how such inhomogeneities affect the possibility to quantify the number of molecules bound to a single nanoparticle. The discussion is based on simulations and measurements of large arrays of well-separated gold nanoparticles fabricated by electron beam lithography (EBL). The new data confirms the intrinsic single-molecule sensitivity of the technique but we were not able to clearly resolve the exact number of adsorbed molecules per single particle. The results indicate that the main sources of uncertainty come from variations in sensitivity across the surface of individual particles and between different particles. There is also a considerable uncertainty in the actual precipitate morphology produced by individual enzyme molecules. Possible routes toward further improvements of the methodology are discussed.

  • 177. Chen, Si
    et al.
    Svedendahl, Mikael
    Duyne, Richard P Van
    Käll, Mikael
    Plasmon-enhanced colorimetric ELISA with single molecule sensitivity.2011Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 11, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Robust but ultrasensitive biosensors with a capability of detecting low abundance biomarkers could revolutionize clinical diagnostics and enable early detection of cancer, neurological diseases, and infections. We utilized a combination of localized surface plasmon resonance (LSPR) refractive index sensing and the well-known enzyme-linked immunosorbent assay to develop a simple colorimetric biosensing methodology with single molecule sensitivity. The technique is based on spectral imaging of a large number of isolated gold nanoparticles. Each particle binds a variable number of horseradish peroxidase (HRP) enzyme molecules that catalyze a localized precipitation reaction at the particle surface. The enzymatic reaction dramatically amplifies the shift of the LSPR scattering maximum, λ(max), and makes it possible to detect the presence of only one or a few HRP molecules per particle.

  • 178.
    Chen, Xi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Photothermal Effect in Plasmonic Nanostructures and its Applications2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

      Plasmonic resonances are characterized by enhanced optical near field and subwavelength power confinement. Light is not only scattered but also simultaneously absorbed in the metal nanostructures. With proper structural design, plasmonic-enhanced light absorption can generate nanoscopically confined heat power in metallic nanostructures, which can even be temporally modulated by varying the pump light. These intrinsic characters of plasmonic nanostructures are investigated in depth in this thesis for a range of materials and nanophotonic applications.

      The theoretical basis for the photothermal phenomenon, including light absorption, heat generation, and heat conduction, is coherently summarized and implemented numerically based on finite-element method. Our analysis favours disk-pair and particle/dielectric-spacer/metal-film nanostructures for their high optical absorbance, originated from their antiparallel dipole resonances.

      Experiments were done towards two specific application directions. First, the manipulation of the morphology and crystallinity of Au nanoparticles (NPs) in plasmonic absorbers by photothermal effect is demonstrated. In particular, with a nanosecond-pulsed light, brick-shaped Au NPs are reshaped to spherical NPs with a smooth surface; while with a 10-second continuous wave laser, similar brick-shaped NPs can be annealed to faceted nanocrystals. A comparison of the two cases reveals that pumping intensity and exposure time both play key roles in determining the morphology and crystallinity of the annealed NPs.

      Second, the attempt is made to utilize the high absorbance and localized heat generation of the metal-insulator-metal (MIM) absorber in Si thermo-optic switches for achieving all-optical switching/routing with a small switching power and a fast transient response. For this purpose, a numerical study of a Mach-Zehnder interferometer integrated with MIM nanostrips is performed. Experimentally, a Si disk resonator and a ring-resonator-based add-drop filter, both integrated with MIM film absorbers, are fabricated and characterized. They show that good thermal conductance between the absorber and the Si light-guiding region is vital for a better switching performance.

      Theoretical and experimental methodologies presented in the thesis show the physics principle and functionality of the photothermal effect in Au nanostructures, as well as its application in improving the morphology and crystallinity of Au NPs and miniaturized all-optical Si photonic switching devices.

  • 179.
    Chen, Xi
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Chen, Yiting
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Shi, Yuechun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Yan, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Qiu, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO. Zhejiang University, China.
    Photothermal switching of SOI-waveguide-based Mach-Zehnder interferometer with integrated plasmonic nanoheater2014Ingår i: Plasmonics, ISSN 1557-1963, Vol. 9, nr 5, s. 1197-1205Artikel i tidskrift (Refereegranskat)
    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.

  • 180.
    Chen, Xi
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Shi, Yuechun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Lou, Fei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Chen, Yiting
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Yan, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Qiu, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO. Zhejiang University, China.
    Photothermally tunable silicon microring-resonator-based optical add-drop filterManuskript (preprint) (Övrigt vetenskapligt)
    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.

  • 181.
    Chen, Xing
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Rinkevicius, Zilvinas
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Cao, Zexing
    Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, China .
    Ruud, Kenneth
    Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsö, Norway.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi (stängd 20110512).
    Zero-point vibrational corrections to isotropic hyperfine coupling constants in polyatomic molecules2011Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 13, nr 2, s. 696-707Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present work addresses isotropic hyperfine coupling constants in polyatomic systems with a particular emphasis on a largely neglected, but a posteriori significant, effect, namely zero-point vibrational corrections. Using the density functional restricted-unrestricted approach, the zero-point vibrational corrections are evaluated for the allyl radical and four of its derivatives. In addition for establishing the numerical size of the zero-point vibrational corrections to the isotropic hyperfine coupling constants, we present simple guidelines useful for identifying hydrogens for which such corrections are significant. Based on our findings, we critically re-examine the computational procedures used for the determination of hyperfine coupling constants in general as well as the practice of using experimental hyperfine coupling constants as reference data when benchmarking and optimizing exchange-correlation functionals and basis sets for such calculations.

  • 182. Chen, Xingxing
    et al.
    Qiu, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Blaikie, Richard J.
    Ding, Boyang
    Illumination Dependent Optical Properties of Plasmonic Nanorods Coupled to Thin-Film Cavities2016Ingår i: Plasmonics, ISSN 1557-1955, E-ISSN 1557-1963, Vol. 11, nr 4, s. 1101-1107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The scattering spectra and intensity of gold nanorods placed at varied distances above gold films have been simulated and measured under various conditions, demonstrating that scattering characteristics of the nanorod-film system are highly dependent on illumination conditions. Studying the surrounding electric fields of nanorods reveals that the illumination-dependent properties of the system are induced by the interference in the nanorod-film system. Both simulations and experiments show that optimising the nanorod-film distance can greatly enhance scattering magnitudes up to similar to 20 times for certain illumination conditions. We propose an application of the studied system in facilitating photo-thermal conversion.

  • 183.
    Chen, Yiting
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Wang, Jing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Chen, Xi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Yan, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Qiu, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Plasmonic analog of microstrip transmission line and effect of thermal annealing on its propagation loss2013Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, nr 2, s. 1639-1644Artikel i tidskrift (Refereegranskat)
    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.

  • 184.
    Chen, Zhihui
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Light manipulation in micro and nano photonic materials and structures2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Light manipulation is an important method to enhance the light-matter interactions in micro and nano photonic materials and structures by generating usefulelectric field components and increasing time and pathways of light propagationthrough the micro and nano materials and structures. For example, quantum wellinfrared photodetector (QWIP) cannot absorb normal incident radiation so thatthe generation of an electric field component which is parallel to the original incident direction is a necessity for the function of QWIP. Furthermore, the increaseof time and pathways of light propagation in the light-absorbing quantum wellregion will increase the chance of absorbing the photons.The thesis presents the theoretical studies of light manipulation and light-matter interaction in micro and nano photonic materials and structures, aiming atimproving the performance of optical communication devices, photonic integrateddevices and photovoltaic devices.To design efficient micro and nano photonic devices, it is essential to knowthe time evolution of the electromagnetic (EM) field. Two-dimensional and three-dimensional finite-difference time-domain (FDTD) methods have been adopted inthe thesis to numerically solve the Maxwell equations in micro and nano photonicmaterials and structures.Light manipulation in micro and nano material and structures studied in thisthesis includes: (1) light transport in the photonic crystal (PhC) waveguide, (2)light diffraction by the micro-scale dielectric PhC and metallic PhC structures(gratings); and (3) exciton-polaritons of semiconductor quantum dots, (4) surfaceplasmon polaritons at semiconductor-metallic material interface for subwavelengthlight control. All these aspects are found to be useful in optical devices of multiplebeam splitter, quantum well/dot infrared photodetectors, and solar cells.

  • 185.
    Cheng, Lihua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Song, Jun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Wang, Jian
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Design of wavelength division demultiplexers based on holographic gratings with a low polarization dependent loss2006Ingår i: Guangzi Xuebao/Acta Photonica Sinica, ISSN 1004-4213, Vol. 35, nr 11, s. 1667-1671Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An optimizing method of main structure parameters (e. g. , the thickness of the crystal) and writing conditions (e. g., the incident angle) is presented for a holographic grating wavelength division demultiplexer based on photorefractive LiNbO3 crystals. The key performance parameters of the demultiplexer, such as the loss and the polarization dependent loss (PDL), are optimized by selecting favourite structure parameters using a rigorous coupled wave analysis method. Numerical results show that a low loss and a low PDL can be achieved by using the optimal crystal thickness and incident angle. The designed demultiplexer obtains the favourite synthetical performance for an actual application. The experimental method of the grating recorded is also introduced in the present paper. The experimental results accorded with theoretical computation commendably by testing the three different specimens.

  • 186.
    Chilo, José
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Feature Extraction for Low-Frequency Signal Classification2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The development of the International Monitoring System (IMS) for the verification of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) has led to a rapid revival of interest in infrasound. Furthermore, the installation of low-frequency sensors at seismic sites has increased in recent years, providing researchers with large and heterogeneous data-sets in near real-time. New techniques are needed to better process all of this data and to extract meaningful information quickly for various applications. In particular, there is a need to find distinct features in the infrasonic signals that allow one to distinguish low level nuclear tests from seismic events.

    In this thesis three methods for feature extraction from infrasound and other types of low frequency signal data are discussed: (1) discrete wavelets transforms (DWTs); (2) time scale spectra (TSSs) using continuous wavelet transforms (CWTs); and (3) empirical mode decomposition (EMD). The dimensionality of the feature space can range from a few to thousands. For processing highdimensional data we use multi-modal data space to find low-dimensional structures. The advantage of this space is that multiple metrics of similarity are converted into one single Euclidean space.

    The overall goal of our research is a system for automatic identification and classification of lowfrequency signals in real-time that is easy to implement in hardware. In this thesis we present our design and implementation of the discrete wavelet transform (DWT) on FPGAs for processing a continuous flow of data to obtain optimal extraction of feature information. FPGA simulation and implementation has been realized by using the polyphase structure, the filter reuse method and techniques such as pipelining and basic operations on the QUARTUS II platform. VHDL has been used to describe the functionality of the discrete wavelet transform and ModelSim has been used for the functional verification.

    Advancements in electronics provide a vital new option for implementation of low-frequency smart sensors that can perform signal processing close to the sensors and transmit the data wirelessly. These smart sensors can improve the efficiency of an automatic classification system and reduce the cost of actual infrasound microphones. The design of a digital wireless data acquisition system using a QF4512 programmable signal converter from Quickfilter Technologies, a MSP430 microcontroller from Texas Instruments and a F2M03GLA Bluetooth module from Free2move for infrasonic records is also presented in this thesis. The digital wireless data acquisition system has passed extensive laboratory and field tests (e.g. with man-made explosions).

    A study of using a miniature 3-axis fluxgate magnetometer to get fingerprints from ferrous objects is also presented in this thesis. In this experiment, distinguishing features of iron samples of four different shapes were determined using wavelet methods. Systematic differences were observed between the signatures of the four shaped iron samples.

  • 187. Cholewa, W
    et al.
    Frid, Wiktor
    KTH, Tidigare Institutioner, Fysik.
    Bednarski, Marcin
    KTH, Tidigare Institutioner, Fysik.
    Identification of loss-of-coolant accidents in LWRs by inverse models2004Ingår i: Nuclear Technology, ISSN 0029-5450, E-ISSN 1943-7471, Vol. 147, nr 2, s. 216-226Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes a novel diagnostic method based on inverse models that could be applied to identification of transients and accidents in nuclear power plants. In particular, it is shown that such models could be successfully applied to identification of loss-of-coolant accidents (LOCAs). This is demonstrated for LOCA scenarios for a boiling water reactor. Two classes of inverse models are discussed: local models valid only in a selected neighborhood of an unknown element in the data set, representing a state of a considered object, and global models, in the form of partially unilateral models, valid over the whole learning data set. An interesting and useful property of local inverse models is that they can be considered as example based models, i.e., models that are spanned on particular sets of pattern data. It is concluded that the optimal diagnostic method should combine the advantages of both models, i.e., the high quality of results obtained from a local inverse model and the information about the confidence interval for the expected output provided by a partially unilateral model.

  • 188.
    Christensen, Henrik
    et al.
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Folkesson, John
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Hedström, Andreas
    UGV technology for urban navigation2004Ingår i: UNMANNED GROUND VEHICLE TECHNOLOGY VI / [ed] Gerhart, GR; Shoemaker, CM; Gage, DW, BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING , 2004, Vol. 5422, s. 191-197Konferensbidrag (Refereegranskat)
    Abstract [en]

    Deployment of humans in an urban setting for search and rescue type missions poses a major risk to the personnel. In rescue missions the risk can stem from debris, gas, etc and in a strategic setting the risk can stem from snipers, mines, gas etc. There is consequently a natural interest in studies of how UGV technology can be deployed for tasks such as reconnaissance, retrieval of objects (bombs, injured people, etc.). Today most vehicles used by the military and bomb squads are tele-operated and without any autonomy. This implies that operation of the vehicles is a stressful and demanding task. Part of this stress can be removed through introduction of autonomous functionality. Autonomy implicitly requires use of map information to allow the system to localize and traverse a particular area, in addition autonomous mapping of an area is a valuable functionality as part of reconnaissance missions to provide an initial inventory of a new area. A host of different sensory modalities can be used for mapping. In general no single modality is, however, sufficient for robust and efficient mapping. In the present study GPS, Inertial Cues, Laser ranging and Odometry is used for simultaneous mapping and localisation in urban environments. The mapping is carried out autonomously using a coverage strategy to ensure full mapping of a particular area. In relation to mapping another important issue is the design of an efficient user interface that allows a regular rescue worker, or a soldier, to operate the vehicle without detailed knowledge about robotics. A number of different designs for user interfaces will be presented and results from studies with a range of end-users (soldiers) will also be reported. The complete system has been tested in an urban warfare facility outside of Stockholm. Detailed results will be reposted from two different test facilities.

  • 189.
    Chung, Nguyen Xuan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Limpens, Rens
    de Weerd, Chris
    Lesage, Arnon
    KTH.
    Fujii, Minoru
    Gregorkiewicz, Tom
    Toward Practical Carrier Multiplication: Donor/Acceptor Codoped Si Nanocrystals in SiO22018Ingår i: ACS Photonics, E-ISSN 2330-4022, Vol. 5, nr 7, s. 2843-2849Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carrier multiplication (CM) is an interesting fundamental phenomenon with application potential in optoelectronics and photovoltaics, and it has been shown to be promoted by quantum confinement effects in nanostructures. However, mostly due to the short lifetimes of additional electronhole (e-h) pairs generated by CM, major improvements of quantum dot devices that exploit CM are limited. Here we investigate CM in SiO2 solid state dispersions of phosphorus and boron codoped Si nanocrystals (NCs): an exotic variant of Si NCs whose photoluminescence (PL) emission energy, the optical bandgap, is significantly red-shifted in comparison to undoped Si NCs. By combining the results obtained by ultrafast induced absorption (IA) with PL quantum yield (PL QY) measurements, we demonstrate CM with a long (around 100 mu s) lifetime of the additional e-h pairs created by the process, similar as previously reported for undoped Si NCs, but with a significantly lower CM threshold energy. This constitutes a significant step toward the practical implementation of Si-based NCs in optoelectronic devices: we demonstrate efficient CM at the energy bandgap optimal for photovoltaic conversion.

  • 190. Clausen, J
    et al.
    Salo, Janne
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Akulin, V M
    Stenholm, Stig Torsten
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Nonclassical dynamics induced by a quantum meter2005Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 72, nr 6, s. 062104-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Conventionally, the effect of measurements on a quantum system is assumed to introduce decoherence, which renders the system classical- like. We consider here a microscopic meter, that is, an auxiliary essentially quantum system whose state is measured repeatedly, and show that it can be employed to induce transitions from classical states into inherently quantumlike states. The meter state is assumed to be lost in the environment and we derive a non- Markovian master equation for the dynamic system in the case of nondemolition coupling to the meter; this equation can be cast in the form of an (N-a)th- order differential equation in time, where N-a is the dimension of the meter basis. We apply the approach to a harmonic oscillator coupled to a spin-1/2 2 meter and demonstrate how it can be used to engineer effective Hamiltonian evolution, subject to decoherence induced by the projective meter measurements.

  • 191.
    Coetzee, Riaan S.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laser induced damage thresholds of KTiOPO4 and Rb:KTiOPO4 at 1 μm and 2 μm2015Ingår i: Conference on Lasers and Electro-Optics Europe - Technical Digest, IEEE conference proceedings, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    Optimum design of high-energy parametric down-conversion schemes mandate investigation of nanosecond laser-induced damage threshold in KTiOPO4 and Rb:KTiOPO4 at 1.064 μm and 2 μm. A surface damage threshold of 10 J/cm2 at 2 μm was determined for both materials.

  • 192.
    Coetzee, Riaan Stuart
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Energy scaling of infrared nanosecond optical parametric oscillators and amplifiers based on Rb:KTiOPO42018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    High-energy, narrowband, nanosecond pulsed mid-infrared sources centred on 2 μm are requiredin applications in remote sensing, standoff detection and pollution monitoring using LIDARs.Currently, space-borne LIDAR missions are under development by major space agencies aroundthe world for active measurements of the atmospheric gas constituents and their dynamics. Thespectral range around 2 μm is one of the windows of operation for these instruments. Opticalparametric oscillators (OPOs) and amplifiers (OPAs) operating at 2 μm are often used as pumpsources for cascaded down-conversion schemes to enable generation of wavelengths deeper intothe mid-infrared. In order to fulfil these purposes, they are required to have high-energy outputwith good overall efficiency, while maintaining a narrowband or tailored spectrum. Moreover, forspace-based instruments, the radiation hardness of the parametric sources needs to be assessed.The central objectives of this thesis were the scaling of the energy and efficiency of 2 μm basedOPOs and OPAs, tailoring their spectral brightness and assessing their suitability for applicationsin space-borne active gas detection systems. Specifically, we investigated OPOs and OPAs basedon periodically-poled Rb:KTiOPO4 (PPRKTP), an engineered nonlinear material which can befabricated with large optical apertures and sub-μm periodicities. One of the key limitations toenergy scaling of these devices is the laser-induced damage threshold (LIDT) of the nonlinearmaterial used. In down-conversion schemes, the devices are subject to both high intensity 1 μmand 2 μm radiation. Prior to the work in this thesis, no LIDT value at 2 μm of KTP and Rb:KTPhad been reported. Furthermore, the work in this thesis provides data on effects of different dosageof gamma radiation on the optical properties of this material and the ways to mitigate the damageinduced by the ionizing radiation. To demonstrate energy scaling with narrow bandwidth andtunability, a nanosecond, master oscillator power amplifier (MOPA) system operating around 2μm and based on large-aperture PPRKTP was built. The MOPA system demonstrated dualnarrowband spectrum, tunable over 1.5 THz by means of a transversally chirped volume Bragggrating, while delivering tens of mJ in output. The output from this MOPA system will be furtherused for tunable THz generation. Even narrower spectra can be generated employing backwardwaveoptical parametric oscillators (BWOPO) based on PPRKTP with the periodicity of 509 nm.This work demonstrates for the first time an efficient, millijoule-level BWOPO with backwardpropagating signal. The device possessed narrowband spectrum with stable output, making it anexcellent seed source in MOPA arrangements.

  • 193.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Duzellier, Sophie
    Dherbecourt, Jean-Baptiste
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Raybaut, Myriam
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Gamma irradiation-induced absorption in single-domain and periodically-poled KTiOPO4 and Rb:KTiOPO42017Ingår i: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, nr 11, s. 4138-4146Artikel i tidskrift (Refereegranskat)
    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.

  • 194.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Nanosecond laser induced damage thresholds in KTiOPO4 and Rb:KTiOPO4 at 1 µm and 2 µm2015Ingår i: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, nr 9, s. 2090-2095Artikel i tidskrift (Refereegranskat)
    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.

  • 195.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlotta
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laser Induced Damage Thresholds of KTP and RKTP2014Konferensbidrag (Refereegranskat)
  • 196.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zheng, Xionghua
    School of Physics, Sun Yat-Sen University.
    Fregnani, Luigi
    Universita di Pavia.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Narrowband, tunable, 2 μm optical parametric master-oscillator power amplifier with large-aperture periodically poled Rb:KTP2018Ingår i: Applied physics. B, Lasers and optics (Print), ISSN 0946-2171, E-ISSN 1432-0649Artikel i tidskrift (Refereegranskat)
    Publikationen är tillgänglig i fulltext från 2020-01-01 15:22
  • 197.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Low-threshold, mid-infrared backward-wave parametric oscillator with periodically poled Rb:KTPManuskript (preprint) (Övrigt vetenskapligt)
  • 198.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Melkonian, Jean-Michel
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    An efficient, 2 µm optical parametric amplifier based on large-aperture periodically poled Rb:KTP2017Ingår i: PROCEEDINGS VOLUME 10562 INTERNATIONAL CONFERENCE ON SPACE OPTICS — ICSO 2016 | 18-21 OCTOBER 2016 International Conference on Space Optics — ICSO 2016, SPIE - International Society for Optical Engineering, 2017, Vol. 10562, artikel-id 105620LKonferensbidrag (Refereegranskat)
    Abstract [en]

    High-energy mid-infrared nanosecond sources are required in a number of applications including biomedicine, remote sensing, and standoff countermeasures, to name just a few. Sources which serve these applications include mid-infrared fiber and solid-state lasers, quantum cascade lasers, as well as optical parametric oscillators (OPO).

  • 199.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    High-energy optical parametric amplifiers in the mid-infrared with large-aperture periodically poled Rb:KTiOPO42016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Parametric down-conversion and amplication schemes are oŸen utilized to obtain high-energy, nanosecond pulses deep within the mid-infrared. We present a high-energy, 2 μm master oscillator power amplier (MOPA) based on large-aperture periodically poled Rb:KTP. A maximum output energy of 52 mJ was obtained with a conversion e›ciency of 40 %.

  • 200.
    Coetzee, Riaan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laser induced damage thresholds at 1 µm and 2 µm for undoped and Rb-doped KTiOPO4 [invited]2015Konferensbidrag (Refereegranskat)
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