Publications
363 results found
Thomas GM, Minassian A, Sheng X, et al., 2016, Diode-pumped Alexandrite lasers in Q-switched and cavity-dumped Q-switched operation, Optics Express, Vol: 24, Pages: 27212-27224, ISSN: 1094-4087
We present the first study of Q-switched Alexandrite lasers under continuous-wave diode-pumping with operation up to 10 kHz repetition rates in TEM00, with spatial quality M2 1.15. With a pulsed-diode dual-end-pumped design, pulse energy is scaled to a record level of 3 mJ. We also demonstrate, for the first time, cavity-dumped Q-switching of diode-pumped Alexandrite lasers under continuous-wave and pulsed diode-pumping, up to 10 kHz. Pulse energy of 510 μJ is demonstrated with 3 ns pulse duration and 170 kW peak power, in TEM00 with M2 < 1.2. Second harmonic generation of the cavity-dumped Q-switched pulses was used to generate UV wavelength 379 nm with conversion efficiency of 47 %.
Kerridge-Johns WR, Damzen MJ, 2016, Analytical model of tunable Alexandrite lasing under diode end-pumping with experimental comparison, Journal of the Optical Society of America B, Vol: 33, Pages: 2525-2534, ISSN: 0740-3224
An analytical model is formulated to support understanding and underpin experimental development of laser action in the promising diode end-pumped Alexandrite system. Closed form solutions are found for output power, threshold, and slope efficiency that for the first time incorporate the combined effects of laser ground state absorption and excited state absorption (laser ESA), along with pump excited state absorption (pump ESA), in the case of an end-pumping geometry. Comparison is made between model predictions and experimental results from a fiber-delivered diode end-pumped Alexandrite laser system, showing the impact of wavelength tuning, crystal temperature, laser output coupling, and intracavity loss. The model is broadly applicable to other quasi-three-level lasers with combined laser and pump ESA. A condition for bistable operation is also formulated.
Arbabzadah EA, Damzen MJ, 2016, Fibre-coupled red diode-pumped Alexandrite TEM00 laser with single and double-pass end-pumping, Laser Physics Letters, Vol: 13, ISSN: 1612-202X
We report the investigation of an Alexandrite laser end-pumped by a fibre-coupled red diode laser module. Power, efficiency, spatial, spectral, and wavelength tuning performance are studied as a function of pump and laser cavity parameters. It is the first demonstration, to our knowledge, of greater than 1 W power and also highest laser slope efficiency (44.2%) in a diode-pumped Alexandrite laser with diffraction-limited TEM00 mode operation. Spatial quality was excellent with beam propagation parameter M 2 ~ 1.05. Wavelength tuning from 737–796 nm was demonstrated using an intracavity birefringent tuning filter. Using a novel double pass end-pumping scheme to get efficient absorption of both polarisation states of the scrambled fibre-delivered diode pump, a total output coupled power of 1.66 W is produced in TEM00 mode with 40% slope efficiency.
Loiko PA, Arbabzadah EA, Damzen MJ, et al., 2015, Judd-Ofelt analysis and stimulated-emission cross-sections for highly doped (38 at%) Er:YSGG laser crystal, Journal of Luminescence, Vol: 171, Pages: 226-233, ISSN: 1872-7883
Stimulated-emission cross-section spectra are determined for the ~1.5 μm and 3 μm transitions of Er3+ ions in YSGG crystal. For the 4I11/2→4I13/2 channel, the maximum stimulated-emission cross-section σSE is 0.43×10−20 cm2 at 2797.1 nm. For the 4I13/2→4I15/2 channel, σSE=1.20×10−20 cm2 at 1532.8 nm. Due to the reabsorption loss, laser operation is expected at ~1644 nm. Radiative lifetimes of all excited states of the Er3+ ion from 4I13/2 to 2H9/2 and probabilities of radiative transitions from these states are determined using the Judd–Ofelt theory. Radiative lifetimes of the 4I13/2 and 4I11/2 excited states for Er3+ ions in YSGG are 7.73 ms and 9.75 ms, respectively. Non-radiative decay is analyzed for lower excited-states of Er3+ ions in YSGG.
Kerridge-Johns WR, Damzen MJ, 2015, Analysis of pump excited state absorption and its impact on laser efficiency, Laser Physics Letters, Vol: 12, ISSN: 1612-202X
Excited state absorption (ESA) is a process that occurs in many laser gain media and can significantly impact their efficiencies of operation. In this work we develop a model to quantify the effect of ESA at the pump wavelength on laser efficiency, threshold and heating. In an analysis based on the common end pumped laser geometry we derive solutions and analytical expressions that model the laser behaviour. From these solutions we discuss the main parameters affecting efficiency, such as the laser cavity loss, pump ESA cross section and stimulated emission cross section. Methodologies are described to minimise the impact of pump ESA, for example by minimising cavity loss. It is also shown that altering the pumping geometry can significantly improve performance by improved distribution of the population inversion. Double end pumping can approximately halve the effect of pump ESA compared to single end pumping, and side pumping also has the potential to arbitrarily reduce its effect.
Thomas GM, Minassian A, Teppitaksak A, et al., 2015, High Energy Q-switching and Cavity Dumped Q-switching of a Diode-pumped Alexandrite Laser, Advanced Solid State Lasers
Thomas GM, Damzen MJ, 2015, Next generation space and airborne laser technology - plenary, SpaceLab 2015
Damzen MJ, Thomas GM, Teppitaksak A, et al., 2015, Diode-Pumped Alexandrite Laser—a new prospect for Remote Sensing, 11th Conference on Lasers and Electro-Optics/Pacific Rim, Publisher: IEEE
Tunable-wavelength diode-pumped Alexandrite laser operation includes highest power > 26W (end-pumped rod); > 12W (side-pumped slab); and first Q-switched operation with pulse energy ~ 1mJ at kHz repetition rate, as development for space lidar application.
Teppitaksak A, Thomas GM, Damzen MJ, 2015, Gain-switched diode laser seeding of ultra-high-gain Nd: YVO 4 bounce amplifier system as a versatile pulsed laser source, The European Conference on Lasers and Electro-Optics, Publisher: OSA Publishing
Thomas GM, Minassian A, Damzen MJ, 2015, Directly diode-side-pumped Alexandrite slab lasers in the bounce geometry and optical vortex generation, The European Conference on Lasers and Electro-Optics
Arbabzadah E, Kerridge-Johns W, Thomas GM, et al., 2015, High efficiency TEM00 diode end-pumped Alexandrite laser, The European Conference on Lasers and Electro-Optics
Teppitaksak A, Thomas GM, Damzen MJ, 2015, Investigation of a versatile pulsed laser source based on a diode seed and ultra-high gain bounce geometry amplifiers, OPTICS EXPRESS, Vol: 23, Pages: 12328-12336, ISSN: 1094-4087
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- Citations: 6
Murphy FJ, Arbabzadah EA, Bak AO, et al., 2015, Optical chopper Q-switching for flashlamp-pumped Er,Cr:YSGG lasers, Laser Physics Letters, Vol: 12, ISSN: 1612-202X
Arbabzadah EA, Kerridge-Johns W, Thomas GM, et al., 2015, High efficiency TEM<inf>00</inf> diode end-pumped Alexandrite laser
Thomas GM, Minassian A, Damzen MJ, 2015, Directly diode-side-pumped alexandrite slab lasers in the bounce geometry and optical vortex generation
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- Citations: 1
Teppitaksak A, Thomas GM, Damzen MJ, 2015, Gain-switched diode laser seeding of ultra-high-gain Nd: YVO<inf>4</inf> bounce amplifier system as a versatile pulsed laser source
Arbabzadah EA, Kerridge-Johns W, Thomas GM, et al., 2015, High efficiency TEM<inf>00</inf> diode end-pumped alexandrite laser
Thomas GM, Minassian A, Damzen MJ, 2015, Directly diode-side-pumped Alexandrite slab lasers in the bounce geometry and optical vortex generation
Teppitaksak A, Thomas GM, Damzen MJ, 2015, Gain-switched diode laser seeding of ultra-high-gain Nd: YVO<inf>4</inf> bounce amplifier system as a versatile pulsed laser source
Thomas GM, Teppitaksak A, Minassian A, et al., 2014, Progress in diode-pumped Alexandrite lasers as a new resource for future space Lidar missions, International Conference on Space Optics
Teppitaksak A, Thomas GM, Damzen MJ, 2014, Gain-switched diode laser seeding of ultra-high-gain Nd: YVO<inf>4</inf> bounce amplifier system as a versatile pulsed laser source
Thomas GM, Minassian A, Damzen MJ, 2014, Directly diode-side-pumped Alexandrite slab lasers in the bounce geometry and optical vortex generation
Arbabzadah EA, Kerridge-Johns W, Thomas GM, et al., 2014, High efficiency TEM<inf>00</inf> diode end-pumped alexandrite laser
Teppitaksak A, Minassian A, Thomas GM, et al., 2014, High efficiency > 26 W diode end-pumped Alexandrite laser, Optics Express, Vol: 22, Pages: 16386-16392, ISSN: 1094-4087
We show for the first time that multi-ten Watt operation of an Alexandrite laser can be achieved with direct red diode-pumping and with high efficiency. An investigation of diode end-pumped Alexandrite rod lasers demonstrates continuous-wave output power in excess of 26W, more than an order of magnitude higher than previous diode end-pumping systems, and slope efficiency 49%, the highest reported for a diode-pumped Alexandrite laser. Wavelength tuning from 730 to 792nm is demonstrated using self-seeding feedback from an external grating. Q-switched laser operation based on polarization-switching to a lower gain axis of Alexandrite has produced ~mJ-pulse energy at 1kHz pulse rate in fundamental TEM00 mode.
Arbabzadah EA, Shardlow PC, Minassian A, et al., 2014, Pulse control in a <i>Q</i>-switched Nd:YVO<sub>4</sub> bounce geometry laser using a secondary cavity, OPTICS LETTERS, Vol: 39, Pages: 3437-3440, ISSN: 0146-9592
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- Citations: 5
Teppitaksak A, Thomas GM, Damzen MJ, 2013, Versatile pulsed source using a pulsed diode seed and ultrahigh gain bounce geometry amplifier
Damzen MJ, Thomas GM, Minassian A, 2013, Multi-watt diode-pumped alexandrite laser operation
Arbabzadah EA, Shardlow PC, Damzen MJ, 2013, Laser pulse control of a Q-switched Nd: YVO<inf>4</inf> bounce geometry laser using a secondary cavity
Arbabzadah EA, Phillips CC, Damzen MJ, 2013, Free-running and Q-switched operation of a diode pumped Er:YSGG laser at the 3 μm transition, APPLIED PHYSICS B-LASERS AND OPTICS, Vol: 111, Pages: 333-339, ISSN: 0946-2171
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- Citations: 17
Damzen MJ, Shadlow PC, 2013, METHOD AND APPARATUS FOR LASER PULSE CONTROL, WO/2013/017338
A method and apparatus for controlling the amplification of radiation in a laser gain are described. By using the controlling action of a secondary radiation path through the common gain element the gain, as seen by the primary radiation path, can be controlled or limited. In one particularly set of embodiments pertaining to laser pulse control of a laser cavity, a laser system is described that comprises first and second laser cavities each including a common laser gain medium. The first cavity incorporates a modulation element for variation of its cavity loss. A second cavity is employed that has a substantially distinct path or separable cavity mode from that of the first cavity. The laser threshold of the second cavity is set to a value intermediate to the extremes of the threshold for the first cavity, corresponding to the maximum and minimum loss available to the modulation element. As a result a more flexible control of laser pulsing and laser performance control is provided. Other embodiments of this invention allow improvement of laser performance through the control of the amplification of the output of a laser system through an external laser amplifier by utilising a secondary radiation path through the external amplifier.
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