3.5 W long-wave infrared ZnGeP<sub>2</sub> optical parametric oscillator at 9.8 µm
Gaoyou Liu, Yi Chen, Baoquan Yao, Ruixue Wang, Ke Yang, Chao Yang, Shuyi Mi, Tongyu Dai, Xiaoming Duan
Abstract
We demonstrated a high-power long-wave infrared optical parametric oscillator at 9.8 µm based on a type-I phase-matching <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">Z</mml:mi> <mml:mi mathvariant="normal">n</mml:mi> <mml:mi mathvariant="normal">G</mml:mi> <mml:mi mathvariant="normal">e</mml:mi> <mml:mi mathvariant="normal">P</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> crystal. By using a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi>Q</mml:mi> </mml:mrow> </mml:math> -switched 2091 nm Ho:YAG laser with pulse repetition frequency of 10 kHz as the pump source, the maximum average output power of 3.51 W at 9.8 µm was achieved with incident pump power of 90 W, corresponding to a slope efficiency of 4.81% and conversion efficiency at maximum pump power of 3.9%. The pulse width of 19.6 ns and linewidth of 142 nm were obtained at maximum output level. In addition, the beam quality factor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mi>M</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> was measured to be <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>2.2</mml:mn> </mml:mrow> </mml:math> .