David Faye

High-efficiency 20–50 kHz mid-infrared orientation-patterned GaAs optical parametric oscillator pumped by a 2 μm holmium laser

We report on what are, to our knowledge, the best results obtained with an orientation-patterned GaAs optical parametric oscillator (OPO) pumped by a Q-switched 2 microm Ho:YAG laser. Up to 2.85 W are obtained for 6.1 W of pump power, corresponding to an optical-to-optical conversion efficiency of 46.5% with a threshold of 1 W. Optical damage occurred at a fluence of about 2 J/cm2. The thickness of the crystal limited the pump power. Slope efficiencies are of the same order as those obtained with ZnGeP2 OPOs pumped with the same Ho:YAG laser.

Broadly tunable single-frequency cw mid-infrared source with milliwatt-level output based on difference-frequency generation in orientation-patterned GaAs

A narrow-linewidth mid-IR source based on difference-frequency generation of an amplified 1.5 microm diode laser and a cw Tm-doped fiber laser in orientation-patterned (OP) GaAs has been developed and evaluated for spectroscopic applications. The source can be tuned to any frequency in the 7.6-8.2 microm range with an output power of 0.5 mW. The measured characteristics of the OP-GaAs sample demonstrate a high quality of the material.

Polarization effects and fiber-laser-pumping of a 2-µm-pumped OP-GaAs OPO

Gallium arsenide combines a large nonlinear coefficient, a good thermal conductivity, excellent mechanical properties, and a wide transparency range (0.9-17μm). Improvement in hybrid vapour phase epitaxy growing techniques of quasiphase- matched orientation-patterned GaAs (OP-GaAs) allows larger sample thickness and permits efficient operation as a mid-infrared optical parametric oscillator at Watt-level average output powers. Especially its low absorption loss (~; 0.01 cm-1), its laser damage threshold comparable to ZGP (~ 2 J/cm2) are suitable properties for efficient non-critical phase matched OPOs. As there is no natural birefringence in GaAs, phase matching is independent of polarization and propagation direction, offering the ability to pump OP-GaAs with a variety of polarization states. Thus, even unpolarized or poorly polarized sources like simple fiber lasers have been efficiently used as pump sources. The paper will discuss recent results obtained with an OP-GaAs OPO directly pumped by a 2.09 μm Q-switched Tm,Ho:silica fiber laser and a study on polarization effects using a Q-switched 2.09 μm Ho:YAG laser as the pump. With a 2.09 μm Q-switched Tm,Ho:silica fiber laser pump source, up to 2.2 W of average output power was achieved at 40 kHz repetition rate, 1.9 W at 60 kHz and 1.3 W at 75 kHz in the mid-infrared range.

High efficiency mid-infrared OPO based on low-loss orientation-patterned GaAs samples (OP-GaAs)

Nonlinear optical materials play a key role in the development of coherent sources of radiation as they permit the frequency conversion of mature solid-state lasers into spectral ranges where lasers do not exist or perform poorly. The availability of efficient quasi-phasematched infrared materials is thus considered as important for the development of several optronics applications. This paper will review the recent progresses achieved with thick Orientation-Patterned GaAs structures. We will present results obtained in growing a 500 μm thick layer on 2 cm long structures with low optical losses (less than 0.02 cm-1). This loss coefficient is low enough to allow the operation of a highly efficient GaAs OPO in the Mid-IR range.

20–50 kHz mid-infrared OP-GaAs OPO

An efficient OP-GaAs OPO pumped by a high repetition rate (20-50 kHz) Q-switched Ho:YAG laser is presented. The slope efficiency is 53% at 20 kHz. Influence of pump polarization on OPO performance is tested.

OP-GaAs OPO pumped by a Q-switched Tm,Ho:silica fiber laser

We report on the first OP-GaAs OPO directly pumped by a 2.09 mum fiber laser. Up to 0.6 W average output power was achieved at 20 kHz repetition rate in the mid-infrared range.

Thick low-loss orientation-patterned gallium arsenide (OP-GaAs) samples for mid-infrared laser sources

Nonlinear optical materials play a key role in the development of coherent sources of radiation as they permit the frequency conversion of mature solid-state lasers into spectral ranges where lasers do not exist or perform poorly. The availability of efficient quasi-phasematched infrared materials is thus considered as important for the development of several defense optronics applications. This paper will review the recent progresses we achieved with thick Orientation Patterned-GaAs structures. We will present results obtained in growing thick-layer (500 µm) on 2 cm long structures with very low optical losses (less than 0.02 cm-1). This loss coefficient is low enough to allow the realization of a high power OPO in the MIR band.

A Widely Tunable CW Mid-Infrared Spectrometer Based on Difference Frequency Generation in Orientation-Patterned GaAs

A widely tunable difference frequency generation based mid-infrared spectrometer for the detection of sulfur dioxide (SO2), nitrous oxide (N2O), and methane (CH4) above 7 µm has been developed for industrial applications.

2-µm-Fiber-Laser-Pumped OP-GaAs OPO and Its Polarization Effects

We report on OP-GaAs OPO directly pumped by 2.09 µm fiber lasers at high repetition rates (40-75 kHz). Up to 2.2 W average output power was achieved at 40 kHz repetition rate in the mid-infrared range

Quasi-phase-matched nonlinear crystals for infrared frequency conversion

Nonlinear optical materials play a key role in the development of coherent sources of radiation as they permit the frequency conversion of mature solid-state lasers into spectral ranges where lasers do not exist or perform poorly. The availability of efficient Quasi-Phase-Matched infrared materials is thus considered as important for the development of several defense optronics applications. This paper will review the progress we achieved so far with periodically oriented Gallium Arsenide.