Laser Diode

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Kazunori Shinoda - One of the best experts on this subject based on the ideXlab platform.

  • Beam-shaping technique for improving the beam quality of a high-power Laser-Diode stack
    Optics Letters, 2006
    Co-Authors: Xin Gao, Masaomi Takasaka, Hiroyuki Ohashi, Hiroshi Okamoto, Kazunori Shinoda
    Abstract:

    We report a beam-shaping technique that reconfigures the beams to improve the beam quality and enhance the power density for a ten-array high-power Laser-Diode stack by using two optical rectangular cubes and two stripe-mirror plates. The reshaped beam has threefold improvement in beam quality, and its power density is effectively enhanced. On the basis of this technique, we focus the beam of the high-power Laser-Diode stack to effectively end pump a high-power fiber Laser.

  • effective suppression of beam divergence for a high power Laser Diode bar by an external cavity technique
    Optics Letters, 2004
    Co-Authors: Xi Gao, Yuji Zheng, Kazunori Shinoda
    Abstract:

    We describe effective suppression of beam divergence for a high-power Laser Diode bar by use of an external-cavity technique. Nineteen off-axis external-cavity Laser Diodes of the high-power Laser Diode are formed by feedback with a stripe mirror. At three times the threshold current, the diverging angle 1/e2 of the external-cavity Laser Diode bar is reduced to 1.5° from 6.6° (free running) with 14.1-W peak output power and 70.4% of the radiated power of the free-running state without the external cavity. This technique effectively improves the beam quality of the high-power Laser Diode bar.

Hirofumi Kan - One of the best experts on this subject based on the ideXlab platform.

  • radiative and nonradiative recombination in an ultraviolet gan algan multiple quantum well Laser Diode
    Applied Physics Letters, 2010
    Co-Authors: Harumasa Yoshida, Yoji Yamashita, Masakazu Kuwabara, Kazuya Uchiyama, Hirofumi Kan
    Abstract:

    We have experimentally investigated the radiative and nonradiative recombination in a GaN/AlGaN multiple-quantum-well Laser Diode. The each carrier lifetime has been evaluated based on a rate equation analysis of light output-current characteristics of the Laser Diode. The estimated nonradiative carrier lifetime is 830 ps, and the Auger recombination is negligibly small at room temperature. At a threshold current density of 8 kA cm−2, the carrier density and the internal quantum efficiency are estimated to be 2.6×1019 cm−3 and 34%, respectively. These results are responsible for experimental and theoretical analysis of optical and electrical properties in AlGaN-based Laser Diodes.

  • efficient operation of a cesium vapor Laser longitudinally pumped by a fine tunable bandwidth narrowed Laser Diode bar
    Japanese Journal of Applied Physics, 2007
    Co-Authors: Yujin Zheng, Minoru Niigaki, Hirofumi Kan
    Abstract:

    We report on a high-power cesium-vapor (Cs-vapor) Laser longitudinally pumped by a tunable external-cavity broad-area Laser-Diode bar. The external cavity consisting of a beam-transformation system and an off-axis volume Bragg grating forced the high-power Laser-Diode bar to emit a fine-tunable narrow-bandwidth beam. Using the tunable narrowed-bandwidth beam, we effectively pumped a Cs-vapor Laser with a flat-concave cavity and obtained strong emission (output peak power, 7 W; slope efficiency, 14%).

  • effective bandwidth reduction for a high power Laser Diode array by an external cavity technique
    Optics Letters, 2005
    Co-Authors: Yujin Zheng, Hirofumi Kan
    Abstract:

    The spectral bandwidth of a high-power Laser-Diode array was effectively suppressed by use of an off-axis external-cavity technique. The external cavity consisted of a beam-transformation system and a pair of off-axis volume Bragg gratings. During operation at a drive current of 40 A, we reduced the bandwidth’s full width at half-maximum from 3.3 to 0.24 nm (14-fold reduction) and achieved an output power of 20 W, or as much as 87% of the power radiated by a free-running Laser-Diode array without an external cavity.

Kyung Hyun Park - One of the best experts on this subject based on the ideXlab platform.

  • Distributed feedback Laser Diode integrated with distributed Bragg reflector for continuous-wave terahertz generation
    Optics Express, 2012
    Co-Authors: Namje Kim, Minyong Jeon, Han-cheol Ryu, Sang-pil Han, Hyunsung Ko, Jeong Woo Park, Donghun Lee, Kyung Hyun Park
    Abstract:

    A widely tunable dual mode Laser Diode with a single cavity structure is demonstrated. This novel device consists of a distributed feedback (DFB) Laser Diode and distributed Bragg reflector (DBR). Micro-heaters are integrated on the top of each section for continuous and independent wavelength tuning of each mode. By using a single gain medium in the DFB section, an effective common optical cavity and common modes are realized. The Laser Diode shows a wide tunability of the optical beat frequency, from 0.48 THz to over 2.36 THz. Continuous wave THz radiation is also successfully generated with low-temperature grown InGaAs photomixers from 0.48 GHz to 1.5 THz.

M A Emanuel - One of the best experts on this subject based on the ideXlab platform.

  • microchannel cooled heatsinks for high average power Laser Diode arrays
    Proceedings of SPIE, 1993
    Co-Authors: William J Benett, B. L. Freitas, Raymond J Beach, M A Emanuel, Dino R Ciarlo, Steven B Sutton, R Solarz
    Abstract:

    Detailed performance results and fabrication techniques for an efficient and low thermal impedance Laser Diode array heatsink are presented. High duty factor or even CW operation of fully filled Laser Diode arrays is enabled at high average power. Low thermal impedance is achieved using a liquid coolant and laminar flow through microchannels. The microchannels are fabricated in silicon using a photolithographic pattern definition procedure followed by anisotropic chemical etching. A modular rack-and-stack architecture is adopted for the heatsink design allowing arbitrarily large two-dimensional arrays to be fabricated and easily maintained. The excellent thermal control of the microchannel cooled heatsinks is ideally suited to pump array requirements for high average power crystalline Lasers because of the stringent temperature demands that result from coupling the Diode light to several nanometers wide absorption features characteristic of lasing ions in crystals.

  • modular microchannel cooled heatsinks for high average power Laser Diode arrays
    IEEE Journal of Quantum Electronics, 1992
    Co-Authors: Raymond J Beach, B. L. Freitas, William J Benett, D Mundinger, Brian J Comaskey, R Solarz, M A Emanuel
    Abstract:

    Detailed performance results for an efficient and low thermal impedance Laser Diode array heatsink are presented. High duty factor or CW operation of fully filled Laser Diode arrays is made possible at high average power. Low thermal impedance is achieved using a liquid coolant and laminar flow through microchannels. The microchannels are fabricated in silicon using an anisotropic chemical etching process. A modular rack-and-stack architecture is adopted for the heatsink design, allowing arbitrarily large two-dimensional arrays to be fabricated and easily maintained. The excellent thermal control of the microchannel cooled heatsinks is ideally suited to pump array requirements for high average power crystalline Lasers. >

B. L. Freitas - One of the best experts on this subject based on the ideXlab platform.

  • Silicon monolithic microchannel-cooled Laser Diode array
    Applied Physics Letters, 2000
    Co-Authors: J. A. Skidmore, B. L. Freitas, J. Satariano, E. Utterback, L. Dimercurio, K. Cutter, J. Crawford, S. Sutton
    Abstract:

    A monolithic microchannel-cooled Laser Diode array is demonstrated that allows multiple Diode-bar mounting with negligible thermal cross talk. The heat sink comprises two main components: a wet-etched Si layer that is anodically bonded to a machined glass block. The continuous wave (cw) thermal resistance of the 10 bar Diode array is which matches the performance of discrete microchannel-cooled arrays. Up to 1.5 is achieved cw at an emission wavelength of Collimation of a Diode array using a monolithic lens frame produced a 7.5 mrad divergence angle by a single active alignment. This Diode array offers high average power/brightness in a simple, rugged, scalable architecture that is suitable for large two-dimensional areas.

  • microchannel cooled heatsinks for high average power Laser Diode arrays
    Proceedings of SPIE, 1993
    Co-Authors: William J Benett, B. L. Freitas, Raymond J Beach, M A Emanuel, Dino R Ciarlo, Steven B Sutton, R Solarz
    Abstract:

    Detailed performance results and fabrication techniques for an efficient and low thermal impedance Laser Diode array heatsink are presented. High duty factor or even CW operation of fully filled Laser Diode arrays is enabled at high average power. Low thermal impedance is achieved using a liquid coolant and laminar flow through microchannels. The microchannels are fabricated in silicon using a photolithographic pattern definition procedure followed by anisotropic chemical etching. A modular rack-and-stack architecture is adopted for the heatsink design allowing arbitrarily large two-dimensional arrays to be fabricated and easily maintained. The excellent thermal control of the microchannel cooled heatsinks is ideally suited to pump array requirements for high average power crystalline Lasers because of the stringent temperature demands that result from coupling the Diode light to several nanometers wide absorption features characteristic of lasing ions in crystals.

  • modular microchannel cooled heatsinks for high average power Laser Diode arrays
    IEEE Journal of Quantum Electronics, 1992
    Co-Authors: Raymond J Beach, B. L. Freitas, William J Benett, D Mundinger, Brian J Comaskey, R Solarz, M A Emanuel
    Abstract:

    Detailed performance results for an efficient and low thermal impedance Laser Diode array heatsink are presented. High duty factor or CW operation of fully filled Laser Diode arrays is made possible at high average power. Low thermal impedance is achieved using a liquid coolant and laminar flow through microchannels. The microchannels are fabricated in silicon using an anisotropic chemical etching process. A modular rack-and-stack architecture is adopted for the heatsink design, allowing arbitrarily large two-dimensional arrays to be fabricated and easily maintained. The excellent thermal control of the microchannel cooled heatsinks is ideally suited to pump array requirements for high average power crystalline Lasers. >

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