2.79-μm mid-infrared Er:YSGG Innoslab laser based on hybrid stable–unstable resonator

We demonstrated an improved-beam-quality improved Er:YSGG laser emitting at wavelength of 2.79 μm by applying the Innoslab hybrid stable–unstable resonator and composite crystal with undoped YSGG section bonded to the pump side. With a space-combined, high peak power 976-nm quasicontinuous laser-diode stack and optimized coupling system, we obtained the maximum average output power of 10.2 W at 100 Hz repetition frequency and 500 μs pulse width, corresponding to the slope efficiency of 16.6%. The beam quality factors of M2 were measured to be 3.3 and 2.6 in the fast and slow axis directions, respectively. To the best of our knowledge, this is the first mid-infrared laser designed with Innoslab hybrid stable–unstable resonator ever reported.