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Browsing by Author "Strauss, Hencharl J"

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330 mJ single-frequency Ho:YLF slab amplifier

Author: Strauss, Hencharl J ; Preussler, D ; Esser, MJD ; Koen, W ; Jacobs, Cobus ; Collett, OJP ; Bollig, C Date: Apr 2013 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 laser and seeded with ... Read more
Beam shaping laser with controllable gain

Author: Litvin, Igor A ; King, Gary R ; Strauss, Hencharl J Date: Jun 2017 We propose a novel intra-cavity laser beam shaping technique based on the manipulation of the transverse gain profile in the laser crystal. The method allows controllable reshaping of a laser output beam into a desired beam profile. Two laser ... Read more
Celebrating the Year of Light….. from medicine to security with Optical Coherence Tomography

Author: Singh, A ; Sharma, Ameeth ; Roberts, T ; Khutlang, Rethabile ; Ramokolo, Lesiba R ; Marome, N ; Webb, L ; Botha, N ; Karsten, A ; Strauss, Hencharl J Date: Oct 2015 This poster Celebrating the Year of Light….. from medicine to security with Optical Coherence Tomography was presented at the CSIR’s 5th Conference, 8-9 October 2015. Read more
Compact fibre-laser-pumped Ho:YLF oscillator-amplifier system

Author: Bollig, C ; Strauss, Hencharl J ; Esser, MJD ; Koen, W ; Schellhorn, M ; Preussler, D ; Nyangaza, K ; Jacobs, Cobus ; Bernhardi, EH ; Botha, LR Date: Jun 2009 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 the polarisation helps ... Read more
Compact fibre-laser-pumped Ho:YLF oscillator–amplifier system

Author: Koen, W ; Bollig, C ; Strauss, Hencharl J ; Schellhorn, M ; Jacobs, Cobus ; Esser, MJD Date: Apr 2010 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 amplified energies agreed ... Read more
Comparative study of thermal lensing in low-doped Nd:YVO4 and Nd:GdVO4 of equal doping concentration

Author: Strauss, Hencharl J ; Bollig, C ; Von Bergmann, M ; Esser, MD Date: Jun 2009 Aimed to compare the two materials directly under diode-end-pumping by performing thermal lens measurements during lasing with a HeNe probe beam using identical low-doped (0.15%), 4x4x18 mm3 crystals. Our setup was such that we could separately ... Read more
Development of high-power and high-energy 2 µm bulk solid-state lasers and amplifiers

Author: Koen, W ; Jacobs, Cobus ; Wu, Lorinda ; Strauss, Hencharl J Date: Apr 2016 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 high-energy, ... Read more
Efficient fiber-laser-pumped Ho:YLF oscillator and amplifier utilizing the transmitted pump power of the oscillator

Author: Strauss, Hencharl J ; Koen, W ; Bollig, C ; Esser, MJD ; Preussler, D ; Nyangaza, K ; Jacobs, Cobus Date: Jun 2009 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 more than 20 mJ energy ... Read more
Exploiting the natural doping gradient of Nd:YLF crystals for high-power end pumped lasers

Author: Bollig, C ; Koen, W ; Strauss, Hencharl J ; Bernhardi, EH ; Botha, R ; Esser, D ; Preussler, DR Date: 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 level lifetime that ... Read more
High average power 1314 nm Nd:YLF laser, passively Q-switched with V:YAG

Author: Botha, RC ; Strauss, Hencharl J ; Bollig, C ; Koen, W ; Collett, O ; Kuleshov, NV ; Esser, MJD ; Combrinck, L ; Von Bergmann, HM Date: Mar 2013 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 absorber in the cavity. ... Read more
High average power Q-switched 1314 nm two-crystal Nd:YLF laser

Author: Botha, RC ; Koen, W ; Esser, MJD ; Bollig, C ; Combrinck, WL ; Von Bergmann, M ; Strauss, Hencharl J Date: Feb 2015 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 inserting a Brewster-cut ... Read more
High Power Vanadate lasers

Author: Strauss, Hencharl J ; Bollig, C ; Botha, RC ; Von Bergmann, HM ; Burger, JP Date: Jul 2006 This presentation aims at the following: to develop new techniques to mount laser crystals; compare the laser properties of two equally doped, high power Nd:YVO4 and Nd: GdVO4 lasers; build a 1um vanadate laser with average output power ... Read more
A high speed OCT system developed at the CSIR National Laser Centre (paper)

Author: Sharma, Ameeth ; Singh, Ann ; Roberts, Ted ; Ramokolo, Lesiba R ; Strauss, Hencharl J Date: Jul 2016 Light-based techniques continue to gain momentum in different spheres of diagnostic and therapeutic applications due to their non-invasive, non-contact properties. One such technique is Optical Coherence tomography (OCT). Since first being ... Read more
High-power diode-end-pumped Tm:YLF slab laser delivering 189 W at 1890 nm

Author: Koen, W ; Strauss, Hencharl J ; Bollig, C ; Esser, MJD Date: Sep 2010 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 1912 nm. At full ... Read more
Ho:YLF & Ho:LuLF slab amplifier system delivering 200 mJ, 2 µm single-frequency pulses

Author: Strauss, Hencharl J ; Koen, W ; Bollig, C ; Esser, MJD ; Jacobs, Cobus ; Collett, OJP ; Preussler, DR Date: Jul 2011 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 seeded with a 69 mJ ... Read more
Multi-pass 1.9 um Tm:YLF slab laser pump source

Author: Strauss, Hencharl J ; Burd, SC ; Koen, W ; Esser, MJD ; Jacobs, Cobus ; Collett, OJP ; Nyangaza, K ; Preussler, D ; Bollig, C Date: Sep 2010 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 a slope efficiency ... Read more
Optically pumped tunable HBr laser in the mid-infrared region

Author: Koen, W ; Jacobs, Cobus ; Bollig, C ; Strauss, Hencharl J ; Esser, MJD ; Botha, LR Date: Jun 2014 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 oscillation was demonstrated ... Read more
Q-switched Ho:YLF laser pumped by a Tm:GdVO4 laser.

Author: Esser, MJD ; Strauss, Hencharl J ; Koen, WS ; Preussler, D ; Nyangaza, K ; Bollig, C Date: Jun 2009 The authors have, through careful analysis of spectroscopic data, designed and demonstrated a diode-end-pumped, quasicontinuous wave Tm:GdVO4 laser operating at 1892 nm in order to pump a Q-switched Ho:YLF laser. The Ho:YLF maximum output ... Read more
Shaping and detecting mid-IR light with a spatial light modulator

Author: Maweza, Elijah L ; Gailele, Lucas M ; Strauss, Hencharl J ; Litvin, Ihar ; Forbes, A ; Dudley, Angela L Date: Oct 2016 We demonstrate the operation and calibration of a spatial light modulator in the mid-IR region by creating and measuring the modal content and wavefront of structured light fields at 2um for the first time. Read more

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