Compact fiber laser-pumped mid-Infrared source based on Orientation-Patterned Gallium Arsenide

摘要

Among quasi-phase matching (QPM) materials, PPLN suffers from a limited transparency, strongly limiting both the output power and the beam quality above 4 μm. We are developing a new QPM technology based on Orientation-Patterned Gallium Arsenide (OP-GaAs) crystals, transparent up to 16 μm and showing excellent nonlinear and thermal properties and very low losses (<0.02 cm~(-1)).rnWe demonstrated with such samples a high-repetition rate tunable OPO attractively pumped by a remote Thulium fiber laser and integrated in a 25×30×6 cm transportable head. A 3 W level output in the 3-5 μm range was obtained with a 53% efficiency and an unprecedented beam quality (M~2=1.4), making this module most suited to study directed infrared countermeasures (DIRCM).