Dispersive optomechanics: a new approach to mechanical quantum systems

by Jack Harris (Yale University)

Tuesday 18 Nov 2008, 11:00 → 12:00 Europe/Stockholm

FA31

Very sensitive mechanical detectors are rapidly approaching a regime in which either the mechanical device itself or its readout should demonstrate quantum behavior. The main technical barrier to reaching this regime has been the difficulty of integrating ultrasensitive micromechanical devices with high-finesse optical cavities. Recently we have developed a robust means for addressing this issue, and have integrated a 50 nm-thick membrane (with a quality factor > 1,000,000) into an optical cavity with a finesse ~ 200,000. Although the membrane is nearly transparent, it couples to the optical cavity dispersively. This coupling is strong enough to laser-cool the membrane from room temperature to 7 mK. In addition, the dispersive nature of the optomechanical coupling allows us to realize a sensitive "displacement squared" readout of the membrane. Such a readout is a crucial requirement for measuring quantum jumps in a mechanical oscillator. We will describe these results, as well as our progress towards observing quantum effects in this system.