LED-pumped whispering-gallery laser

A low-cost light-emitting diode (LED) is sufficient to pump a quasi-continuous-wave bidirectional high-Q whispering-gallery resonator laser made of Nd:YVO4. This is remarkable because of the very limited spatial and spectral coherence of an LED. The LED, delivering up to 3.5 W, centered around 810 nm, is turned on in intervals of 100 µs duration, and for these periods a laser output exceeding 0.8 mW has been verified. Furthermore, 0.1-s-long laser pulses are demonstrated. To the best of our knowledge this is the first demonstration of an LED-pumped high-Q whispering-gallery laser. The concept can be extended easily to other laser active materials. A prospect is also to pump several of such lasers with a single LED.