A hybrid quantum cascade laser/Fe:ZnSe amplifier system for power scaling of CW lasers at 4.0-4.6 m

A hybrid continuous-wave Fe:ZnSe laser amplifier seeded with a mid-infrared quantum cascade laser is demonstrated. A maximum output power of 870 mW with an extraction efficiency of 30 % was achieved from the Fe:ZnSe amplifier seeded by a 200-mW laser at 4.0 mu m, corresponding to a gain of approximately 4.4. When the amplifier was seeded by a 150-mW laser at 4.6 mu m, an effective gain of approximately 1.4 was obtained. Additionally, we present a theoretical analysis to provide possible routes for further optimization of this Fe:ZnSe amplifier system.