UC Santa Barbara

The quantum to classical transition in large mechanical systems is still a mystery. An ideal tool for exploring this new regime of physics is cavity optomechanics. The field of optomechanics uses light in an optical cavity to finely control and detect mechanical motion. Remarkable progress has been made in recent years with the generation of non-classical states of motion. If such states can be extended into the macroscopic regime, new physics may emerge due to the unprecedented scale.

In this dissertation we work towards the goal of macroscopic quantum optomechanics by developing new mechanical devices, experimental techniques and experimental protocols. First we fabricate nested trampoline resonators, devices with high mechanical quality factor, excellent vibrational isolation from the mechanical environment and mirrors which can support high finesse cavities. With these devices we explore a new optomechanical interaction in which spatially separated, nondegenerate mechanical modes can exchange their state. Finally, we investigate theoretically how this interaction can generate a quantum entangled state between multiple mechanical modes, bypassing many experimental difficulties of previously proposed schemes. These developments help pave the way towards phonon interference experiments in macroscopic resonators.