High-power 1176 nm vortex beam generated in a Nd:YVO4 self-Raman laser via annular pumping

Abstract Optical vortices carrying orbital angular momentum are of marked importance for a myriad of practical applications. We demonstrate the direct generation of high-power (watt-level) Laguerre–Gaussian vortex beam (LG 01 with radial index p = 0 and azimuthal index l = 1) in a continuous-wave Nd:YVO 4 self-Raman laser at 1176 nm with annular pumping by an axicon. Under an absorbed pump power of 17.17 W, a maximum vortex Raman output of 1.43 W was achieved with an optical conversion efficiency of 8.3%. The Stokes output beam has a stable helical wavefront with well-determined handedness at high pump power. Furthermore, selective generation of LG 01 modes with opposite handedness can be realized simply by breaking azimuthal symmetry by tilting the output coupler. The results show that the annular pumping by an axicon has great potential in the development of compact Raman vortex laser systems with high power, high beam quality and versatile laser wavelengths.