Efficient conversion of Nd:YAG laser radiation to the eye-safe spectral region by stimulated Raman scatteringin BaWO4 crystal

The possibility of increasing the efficiency of one-cascade 1.5-mu m SRS lasing in a BaWO4 crystal placed into an external SRS cavity and pumped by a nanosecond Nd:YAG laser at a wavelength of 1.34 mu m is studied. Conditions that prevent energy outflow to the second Stokes SRS component with a wavelength of 1.78 mu m are found, which allowed us to increase the efficiency of one-cascade intracavity SRS lasing at 1.53 mu m up to 60% and the slope efficiency upto the quantum limit (similar to 80% at the SRS pulse energy upto 20 mJ). The use of pumping by laser pulse trains provided the possibility of increasing the 1.53-mu m SRS radiation energy to 40 mJ in a three-pulse train.