Two-mJ level, high-energy all-passive KGW/Tm:YLF Raman laser

This paper presents an all-passive external cavity KGW Raman laser in the 2-μm spectral range, pumped by a Tm:YLF laser at 1879.5 nm. The Raman laser emits two lines at 2197 nm and 2263 nm achieving maximum energy outputs of 1.86 mJ and 2.08 mJ, and conversion efficiencies of 40% and 45.3%, respectively. To the best of our knowledge, this laser performance is a new record in terms of energy per pulse and conversion efficiency, surpassing the two-mJ level for the first time by stimulated Raman scattering in the 2-μm range in an all-passive configuration.