Second harmonic generation in a high-Q lithium niobate microresonator fabricated by femtosecond laser micromachining

We report on fabrication of high Q lithium niobate (LN) whispering-gallery-mode (WGM) microresonators suspended on silica pedestals by femtosecond laser microfabrication. The micrometer-scale (diameter ~82 {\mu}m) LN resonator possesses a Q factor of 2.5x10^5 around 1550 nm wavelength range. Moreover, second harmonic generation with a continuous-wave tunable single-longitudinal-mode pump laser in the on-chip LN microresonator is demonstrated in the on-chip LN microresonator. A fiber taper is employed to couple the pump laser into the microresonator, showing a normalized conversion efficiency of 1.35x10^-5/mW.