Real-time electrical tuning of an optical spring on a monolithically integrated ultrahigh Q lithium nibote microresonator

Cavity optomechanics, the study of the interplay between light and mechanical properties of matter, has triggered a wide range of research from cavity quantum electrodynamics, label-free single molecule detection to the creation of phonon lasers. Using femtosecond laser direct writing followed by chemomechanical polishing, here we report an ultrahigh quality (Q∼10⁷) factor lithium niobate whispering gallery microresonator monolithically integrated with inplane microelectrodes. Coherent regenerative optomechanical oscillation with an effective mechanical quality factor as high as 2.86×10⁸ is observed in air. We demonstrate real-time electrical tuning of the optomechanical frequency with an electromechanical tuning efficiency around -134 kHz/100 V.