Cascaded Raman microlaser in air and buffer

Optical microcavities provide an intriguing platform for the development of low threshold microlasers based on nonlinear effects. Long photon lifetimes within the cavity translate to high circulating optical intensities, thereby reducing the lasing threshold. It is therefore possible to create lasers that can operate in complex environments. In the present work, we use a silica microsphere to demonstrate a cascaded Raman microlaser that operates in air and buffer with the first emission peak around 800 nm in both environments. As expected, the threshold in air is significantly lower than in buffer.