Diamond Raman Vortex Lasers

For the first time, a cascaded diamond Raman vortex laser directly emitting within the cavity has been reported. Employing a two-mirror structured diamond Raman oscillator pumped by a 1064 nm Gaussian laser, first- and second-order Raman transitions yielded outputs at 1240 and 1485 nm, respectively. By incorporating the off-axis rotation of cavity mirrors, both wavelength bands produced spatially symmetrical distributions of Hermite–Gaussian (HG) and Laguerre–Gaussian (LG) vortex beams. The achieved maximum output powers for the first and second Stokes vortex lasers were 42 and 22 W, respectively, corresponding to conversion efficiencies of 15.3% and 5.8%. Benefiting from diamond's exceptional thermal properties, no saturation or decline in the Raman vortex output power was observed within the experimental pump power range. The straightforward off-axis adjustment methodology introduced into a diamond Raman cavity with superior optical and thermal characteristics enables direct dual-wavelength vortex emission, validating diamond Raman oscillators as an effective means of expanding the wavelength of the vortex laser. This breakthrough holds significant implications for expanding the working wavelengths and output powers of vortex beams.