High efficiency ethane Raman laser pumped by 532 nm laser

Abstract

In this work, 532 nm laser was used as the pump source and pressurized ethane was used as Raman active medium; 631.3 nm first Stokes (S1) and 776.0 nm second Stokes (S2) Raman lasers were generated. By the optimization of ethane pressure and focus lens, S2 and backwards first Stokes Raman conversion could be reduced, while the conversion of S1 could be improved. Under 2.0 MPa ethane and focal length of 1.5 m, the maximum S1 conversion efficiency of 84.5% was achieved. Up to 68.7 mJ S1 Raman laser was obtained, and the corresponding peak power is 17.2 MW. By the comparison of the threshold of methane Raman laser, Raman gain coefficients of ethane were estimated to be 0.50 × 10−12 m/W at 0.5 MPa and 0.76 × 10–12 m/W at 1.4 MPa ethane respectively.