Efficient telecom to visible wavelength conversion in doubly resonant gallium phosphide microdisks

Resonant second harmonic generation between 1550 nm and 775 nm with normalized outside efficiency > 3: 8 x 10(-4) mW(-1) is demonstrated in a gallium phosphide microdisk supporting high-Q modes at visible (Q similar to 10(4)) and infrared (Q similar to 10(5)) wavelengths. The double resonance condition is satisfied for a specific pump power through intracavity photothermal temperature tuning using similar to 360 mu W of 1550 nm light input to a fiber taper and coupled to a microdisk resonance. Power dependent efficiency consistent with a simple model for thermal tuning of the double resonance condition is observed. (C) 2016 AIP Publishing LLC.