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Browsing by Author "Koen, W"

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  • Strauss, HJ; Preussler, D; Esser, MJD; Koen, W; Jacobs, Cobus; Collett, OJP; Bollig, C (Optical Society of America, 2013-04)
    We report on a double-pass Ho:YLF slab amplifier which delivered 350 ns long single-frequency pulses of up to 330 mJ at 2064 nm, with a maximum M(sup2) of 1.5 at 50 Hz. It was end pumped with a diode-pumped Tm:YLF slab ...
  • Bollig, C; Strauss, HJ; Esser, MJD; Koen, W; Schellhorn, M; Preussler, D; Nyangaza, K; Jacobs, Cobus; Bernhardi, EH; Botha, LR (IEEE, 2009-06)
    Ho:YLF is an attractive laser material for 2 µm high energy sources since it has a much longer upper laser level lifetime (~14 ms) and higher emission cross section than Ho:YAG. In addition, the very weak thermal lens on ...
  • Koen, W; Bollig, C; Strauss, H; Schellhorn, M; Jacobs, Cobus; Esser, MJD (American Institute of Physics, 2010-04)
    The authors developed a compact Ho:YLF oscillator–amplifier system in a novel setup to utilise the unpolarised pump power from a fibre laser efficiently, and produced 21.3 mJ at 1 kHz, with an M 2 better than 1.1. The ...
  • Koen, W; Jacobs, Cobus; Wu, Lorinda; Strauss, H (SPIE, 2016-04)
    A selection of 2 µm lasers and amplifiers developed at the CSIR National Laser Centre in South Africa is presented. A diverse range of near diffraction-limited 2 µm lasers and amplifiers were developed which varied from ...
  • Strauss, HJ; Koen, W; Bollig, C; Esser, MJD; Preussler, D; Nyangaza, K; Jacobs, Cobus (OSA/CLEO/IQEC, 2009-06)
    In this paper, researchers have demonstrated that a Ho:YLF oscillator and amplifier system can be designed in a compact setup where the pump power from an unpolarized fibre laser utilized efficiently. The system produced ...
  • Koen, W; Jacobs, Cobus; Collett, O (2013-07)
    Laser sources emitting in the 2 micron region is of particular interest for applications in medicine, remote sensing (LIDAR) and directed infra-red countermeasures. In addition, they are also desirable pump sources for ...
  • Koen, W; Jacobs, Cobus; Collett, O; Esser, MJD (The Optical Society, 2013-10)
    A thulium fiber laser pumped Ho:YLF laser delivering 45.1 W in a near diffraction limited beam when pumped with 84.7 W is demonstrated. The optical-to-optical efficiency of 53 % compares favorably with similar Ho:YAG lasers.
  • Bollig, C; Koen, W; Strauss, H; Bernhardi, EH; Botha, R; Esser, D; Preussler, DR (2008)
    Of the various Neodymium-doped materials, Nd:YLF is particularly attractive for use in high-power diode endpumped solid-state lasers due to its weak thermal lens, especially on the σ-polarisation, and it’s long upper laser ...
  • Botha, RC; Strauss, HJ; Bollig, C; Koen, W; Collett, O; Kuleshov, NV; Esser, MJD; Combrinck, L; Von Bergmann, HM (Optical Society of America, 2013-03)
    A 1314 nm Nd:YLF laser was designed and operated both CW and passively Q-switched. Maximum CW output of 10.4 W resulted from 45.2 Wof incident pump power. Passive Q-switching was obtained by inserting a V:YAG saturable ...
  • Botha, RC; Koen, W; Esser, MJD; Bollig, C; Combrinck, WL; Von Bergmann, M; Strauss, HJ (Optical Society of America, 2015-02)
    A 1314 nm two-crystal Nd:YLF laser was designed and operated in both CW and actively Q-switched modes. Maximum CW output of 26.5 W resulted from 125 W of combined incident pump power. Active Q-switching was obtained by ...
  • Koen, W; Strauss, H; Bollig, C; Esser, MJD (South African Institute of Physics, 2010-09)
    The authors present a high-power Tm:YLF slab laser double-end-pumped by two 300 W laser diode stacks. The resonator was designed such that the laser emitted at 1890 nm instead of the conventional operating wavelength of ...
  • Strauss, HJ; Koen, W; Bollig, C; Esser, MJD; Jacobs, Cobus; Collett, OJP; Preussler, DR (Optical Society of America, 2011-07)
    A single-frequency single-pass amplifier based on Ho:YLF and Ho:LuLF in a scalable slab architecture delivering up to 210 mJ at 2064 nm is demonstrated. The amplifier was end-pumped by a 1890 nm Tm:YLF slab laser and was ...
  • Strauss, HJ; Burd, SC; Koen, W; Esser, MJD; Jacobs, Cobus; Collett, OJP; Nyangaza, K; Preussler, D; Bollig, C (2010-09)
    A novel multi-pass Tm: YLF laser was demonstrated with an improvement in efficiency, footprint and cost over a two diode stack pumped, single pass system. 100 W of output power from 261 W of incident diode pump power with ...
  • Koen, W; Jacobs, Cobus; Bollig, C; Strauss, HJ; Esser, MJD; Botha, LR (Optical Society of America, 2014-06)
    An optically pumped tunable HBr laser has been demonstrated for the first time. The pump source was a single-frequency Ho:YLF laser and amplifier system, which was locked to the 2064 nm absorption line of HBr. Laser ...