Extracavity pumped parametric Raman nanosecond crystalline anti-Stokes laser at 954 nm with collinear orthogonally polarized beam interaction at tangential phase matching

Abstract

The extracavity parametric Raman CaCO₃ anti-Stokes laser at 954 nm excited by two orthogonally polarized (pump and probe) equal frequency laser beams was proposed and investigated. Tangential phase matching conditions for the orthogonally polarized Raman components four-wave mixing in the CaCO₃ crystal at stimulated Raman scattering (SRS) under 1064-nm excitation were theoretically studied and applied for a novel nanosecond parametric Raman laser allowing to increase the 954-nm anti-Stokes generation efficiency. In agreement with the theoretical modeling, using the high-Q external cavity scheme we have experimentally achieved the highest optical-to-optical (1064 nm to 954 nm) efficiency of 4% in comparison with the known crystalline parametric Raman anti-Stokes lasers. The ~3 ns anti-Stokes output pulse energy was 0.3 mJ with high beam quality factor M² = 1.1 × 1.2.