A continuous-wave frequency-doubled Nd:GdVO₄ Raman laser at 586.5nm using intracavity adaptive optics

All-solid-state Raman lasers have recently been developed to access a range of wavebands that are difficult to obtain using common crystalline lasers [1]. When combined with sum frequency generation or second harmonic generation, a range of visible spectra can be produced for many applications in medicine, microscopy and remote sensing. Typically, an intracavity Raman laser configuration using a separate Raman gain medium inserted inside a resonator can significantly reduce the pump requirement due to its high intracavity power intensity. A simpler cavity design with reduced optical losses can be achieved by using a self-Raman laser configuration where the laser and Raman gain media are shared in the same crystal [2]. However, due to the simultaneous residual pump loading and the nonelastic nature of Stimulated Raman Scattering occurring within the self-Raman gain medium, a complex superposition of thermal lensing is generated and results in a strong thermo-optical distortion inside the cavity. This thermal lens scales directly with the Raman laser output and has been identified as the main limitation in the power-scaling of continuous-wave Raman lasers [3].