The Experts below are selected from a list of 35352 Experts worldwide ranked by ideXlab platform
Wencheng Xu - One of the best experts on this subject based on the ideXlab platform.
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tunable and switchable multiwavelength erbium doped fiber ring laser based on a modified dual pass mach zehnder interferometer
Optics Letters, 2009Co-Authors: Wencheng XuAbstract:A tunable and switchable multiwavelength erbium-doped fiber ring laser based on what we believe to be a new type of tunable comb filter is proposed and demonstrated. By adjusting the polarization controllers, the dual-function operation of the channel-spacing tunability and the wavelength switching (interleaving) can be readily achieved. Up to 29 stable Lasing lines with 0.4 nm spacing and 14 Lasing wavelengths with 0.8 nm spacing in 3 dB bandwidth were obtained at room temperature. In addition, the Lasing output, including the number of the Lasing lines, the Lasing evenness, and the Lasing locations, can also be flexibly adjusted through the wavelength-dependent polarization rotation mechanism.
Yoshiaki Nakata - One of the best experts on this subject based on the ideXlab platform.
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modeling room temperature Lasing spectra of 1 3 μm self assembled inas gaas quantum dot lasers homogeneous broadening of optical gain under current injection
Journal of Applied Physics, 2005Co-Authors: Mitsuru Sugawara, Nobuaki Hatori, H Ebe, M Ishida, Y Arakawa, T Akiyama, Koji Otsubo, Yoshiaki NakataAbstract:We studied the injection current dependence of room-temperature Lasing spectra of a 1.3-μm self-assembled InAs∕GaAs quantum-dot laser both experimentally and theoretically. Starting from the ground-state Lasing with a few longitudinal modes, the spectra showed splitting, broadening, excited-state Lasing, and quenching of the ground-state Lasing as the current increased. We could explain this unique current dependence by numerical simulation based on our quantum-dot laser theory, taking into account the inhomogeneous and homogeneous broadening of the optical gain as well as the carrier relaxation processes in the spatially isolated quantum dots. Through the simulation, we found that the homogeneous broadening of the ground state is kept between 5 and 10 meV under the ground-state Lasing, while it increases up to 20 meV under the excited-state Lasing.
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light emission spectra of columnar shaped self assembled ingaas gaas quantum dot lasers effect of homogeneous broadening of the optical gain on Lasing characteristics
Applied Physics Letters, 1999Co-Authors: Mitsuru Sugawara, Kohki Mukai, Yoshiaki NakataAbstract:We examined the current–output power characteristics and light emission spectra for columnar-shaped self-assembled InGaAs quantum-dot lasers with a room temperature Lasing threshold of 6 mA. Lasing threshold currents became obscure as temperature decreased below 180 K. While Lasing occurred with one line including a series of longitudinal modes at room temperature, spectra at 80 K showed broad Lasing emission over a range of 50–60 meV. We conclude that dots with different energies start Lasing independently at low temperatures due to their spatial localization, while at room temperature the dots contribute to one-line Lasing collectively via homogeneous broadening of optical gain.
Irina A. Buyanova - One of the best experts on this subject based on the ideXlab platform.
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dilute nitride nanowire lasers based on a gaas ganas core shell structure
Nano Letters, 2017Co-Authors: Shula Chen, Mattias Jansson, Jan E. Stehr, Yuqing Huang, Fumitaro Ishikawa, Weimin Chen, Irina A. BuyanovaAbstract:Nanowire (NW) lasers operating in the near-infrared spectral range are of significant technological importance for applications in telecommunications, sensing, and medical diagnostics. So far, Lasing within this spectral range has been achieved using GaAs/AlGaAs, GaAs/GaAsP, and InGaAs/GaAs core/shell NWs. Another promising III–V material, not yet explored in its Lasing capacity, is the dilute nitride GaNAs. In this work, we demonstrate, for the first time, optically pumped Lasing from the GaNAs shell of a single GaAs/GaNAs core/shell NW. The characteristic “S”-shaped pump power dependence of the Lasing intensity, with the concomitant line width narrowing, is observed, which yields a threshold gain, gth, of 3300 cm–1 and a spontaneous emission coupling factor, β, of 0.045. The dominant Lasing peak is identified to arise from the HE21b cavity mode, as determined from its pronounced emission polarization along the NW axis combined with theoretical calculations of Lasing threshold for guided modes inside the...
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Dilute Nitride Nanowire Lasers Based on a GaAs/GaNAs Core/Shell Structure
2017Co-Authors: Shula Chen, Mattias Jansson, Jan E. Stehr, Yuqing Huang, Fumitaro Ishikawa, Weimin M. Chen, Irina A. BuyanovaAbstract:Nanowire (NW) lasers operating in the near-infrared spectral range are of significant technological importance for applications in telecommunications, sensing, and medical diagnostics. So far, Lasing within this spectral range has been achieved using GaAs/AlGaAs, GaAs/GaAsP, and InGaAs/GaAs core/shell NWs. Another promising III–V material, not yet explored in its Lasing capacity, is the dilute nitride GaNAs. In this work, we demonstrate, for the first time, optically pumped Lasing from the GaNAs shell of a single GaAs/GaNAs core/shell NW. The characteristic “S”-shaped pump power dependence of the Lasing intensity, with the concomitant line width narrowing, is observed, which yields a threshold gain, gth, of 3300 cm–1 and a spontaneous emission coupling factor, β, of 0.045. The dominant Lasing peak is identified to arise from the HE21b cavity mode, as determined from its pronounced emission polarization along the NW axis combined with theoretical calculations of Lasing threshold for guided modes inside the nanowire. Even without intentional passivation of the NW surface, the Lasing emission can be sustained up to 150 K. This is facilitated by the improved surface quality due to nitrogen incorporation, which partly suppresses the surface-related nonradiative recombination centers via nitridation. Our work therefore represents the first step toward development of room-temperature infrared NW lasers based on dilute nitrides with extended tunability in the Lasing wavelength
Mitsuru Sugawara - One of the best experts on this subject based on the ideXlab platform.
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modeling room temperature Lasing spectra of 1 3 μm self assembled inas gaas quantum dot lasers homogeneous broadening of optical gain under current injection
Journal of Applied Physics, 2005Co-Authors: Mitsuru Sugawara, Nobuaki Hatori, H Ebe, M Ishida, Y Arakawa, T Akiyama, Koji Otsubo, Yoshiaki NakataAbstract:We studied the injection current dependence of room-temperature Lasing spectra of a 1.3-μm self-assembled InAs∕GaAs quantum-dot laser both experimentally and theoretically. Starting from the ground-state Lasing with a few longitudinal modes, the spectra showed splitting, broadening, excited-state Lasing, and quenching of the ground-state Lasing as the current increased. We could explain this unique current dependence by numerical simulation based on our quantum-dot laser theory, taking into account the inhomogeneous and homogeneous broadening of the optical gain as well as the carrier relaxation processes in the spatially isolated quantum dots. Through the simulation, we found that the homogeneous broadening of the ground state is kept between 5 and 10 meV under the ground-state Lasing, while it increases up to 20 meV under the excited-state Lasing.
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light emission spectra of columnar shaped self assembled ingaas gaas quantum dot lasers effect of homogeneous broadening of the optical gain on Lasing characteristics
Applied Physics Letters, 1999Co-Authors: Mitsuru Sugawara, Kohki Mukai, Yoshiaki NakataAbstract:We examined the current–output power characteristics and light emission spectra for columnar-shaped self-assembled InGaAs quantum-dot lasers with a room temperature Lasing threshold of 6 mA. Lasing threshold currents became obscure as temperature decreased below 180 K. While Lasing occurred with one line including a series of longitudinal modes at room temperature, spectra at 80 K showed broad Lasing emission over a range of 50–60 meV. We conclude that dots with different energies start Lasing independently at low temperatures due to their spatial localization, while at room temperature the dots contribute to one-line Lasing collectively via homogeneous broadening of optical gain.
Yoshihisa Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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low threshold znse microdisk laser based on fluorine impurity bound exciton transitions
Microelectronics Journal, 2009Co-Authors: A Pawlis, M Panfilova, K Sanaka, Thaddeus D Ladd, K Lischka, Yoshihisa YamamotoAbstract:Impurity states in semiconductors, in which two long-lived ground states can be optically coupled to a single excited state, provide a powerful mechanism for applications including Lasing without inversion, electromagnetically induced transparency, and optically addressable quantum memory for quantum information processing. We report low-threshold Lasing from fluorine-doped ZnMgSe/ZnSe quantum wells in microdisk cavities. The Lasing mechanism was studied by power-dependent photoluminescence spectroscopy. Lasing thresholds lower than 50Wcm^-^2 were observed and the fraction of spontaneous emission contributed to the Lasing modes was about @b=0.03-0.1.
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polariton Lasing vs photon Lasing in a semiconductor microcavity
Proceedings of the National Academy of Sciences of the United States of America, 2003Co-Authors: Hui Deng, Gregor Weihs, D W Snoke, J Bloch, Yoshihisa YamamotoAbstract:Nearly one decade after the first observation of Bose–Einstein condensation in atom vapors and realization of matter-wave (atom) lasers, similar concepts have been demonstrated recently for polaritons: half-matter, half-light quasiparticles in semiconductor microcavities. The half-light nature of polaritons makes polariton lasers promising as a new source of coherent and nonclassical light with extremely low threshold energy. The half-matter nature makes polariton lasers a unique test bed for many-body theories and cavity quantum electrodynamics. In this article, we present a series of experimental studies of a polariton laser, exploring its properties as a relatively dense degenerate Bose gas and comparing it to a photon laser achieved in the same structure. The polaritons have an effective mass that is twice the cavity photon effective mass, yet seven orders of magnitude less than the hydrogen atom mass; hence, they can potentially condense at temperatures seven orders of magnitude higher than those required for atom Bose–Einstein condensations. Accompanying the phase transition, a polariton laser emits coherent light but at a threshold carrier density two orders of magnitude lower than that needed for a normal photon laser in a same structure. It also is shown that, beyond threshold, the polariton population splits to a thermal equilibrium Bose–Einstein distribution at in-plane wave number k∥ > 0 and a nonequilibrium condensate at k∥ > 0, with a chemical potential approaching to zero. The spatial distributions and polarization characteristics of polaritons also are discussed as unique signatures of a polariton laser.
