High-power Raman lasing and efficient anti-Stokes generation in mm-sized crystalline disk resonators

We have previously experimentally observed high-power Stokes and second-order Stokes output from a mm-sized CaF 2 disk using stimulated Raman scattering. A pump laser at a wavelength of 1.06 µ m was coupled via a tapered fiber to the whispering gallery modes (WGM) of the disk. In this Letter, we extend this work and demonstrate the production of the first anti-Stokes sideband at power levels as high as 60 µ W in near continuous-wave (CW) operation. The result is a four-component Raman comb at the output, with a wavelength range covering from 1.023 to 1.14 µ m. We discuss the threshold dependence of the observed Raman lines on the crystal orientation and provide experimental validation. These advances enable the use of such mm-sized resonators as compact, efficient sources for terahertz-level frequency modulation.