High beam quality and high peak power 1.6 µm deuterium Raman laser

In this work, a 1.67 µm laser was generated in the pressurized deuterium pumped by a pulsed 1064 nm laser via the stimulated vibration + rotation Raman scattering (SV-RRS). By the optimization of the deuterium pressure, focal length, and polarization of the pump laser, a 66.2 mJ Raman laser was achieved with the configuration of 1.7 MPa deuterium pressure, 2245 mm focal length, and 220 mJ circularly polarized pump laser. Correspondingly, the photon conversion efficiency was 47.8%, the energy conversion efficiency was 30.5%, the pulse width was 5.4 ns, and the maximum peak power was 12.3 MW. In addition, SV-RRS was found to improve beam quality significantly: from M_x ²= 2.67 and M_y ²= 3.07 for the pump laser to M_x ²= 1.42 and M_y ²= 1.53 for the 1.67 µm Raman laser.