Prolonged Raman lasing in size-stabilized salt-water microdroplets on a superhydrophobic surface

Abstract

We demonstrate prolonged Raman lasing from individual salt-water microdroplets with 10-20 mu m diameters located on a superhydrophobic surface. The mechanism is based on the absorption heating of a 1064 nm cw IR laser and the resonant heating of a 532 nm pulsed, pump laser. A clear hysteresis is observed in the lasing intensity as the droplet size is photothermally tuned by the IR laser, indicating a self-stabilization mechanism due to the resonant absorption of the pump laser. Using this mechanism, Raman lasing near 650 nm is sustained for up to 25 min, similar to 1000 times longer than lasing durations reported in previous studies.