Continuous-wave emission from a self-Raman vortex laser

The unique characteristics of vortex laser beams (having annular spatial profile and orbital angular momentum) have seen them applied in a host of applications [1]. These beams are often produced through conversion of a Gaussian to a Laguerre Gaussian (LG) beam using extra cavity methods such as spiral phase plates and spatial light modulators [1]. However, an alternative method of generating these beams, which may also yield better beam quality and overall power is to force the laser to directly oscillate on an LG mode. This can been achieved using methods such as pumping with an annular shaped beam [2], using thermal lensing [3], or by using a defect spot on a resonator mirror [4].