We describe the design, fabrication, and characterization of aone-dimensional silicon photonic crystal cavity in which a central slot is usedto enhance the overlap between highly localized optical and mechanical modes.The optical mode has an extremely small mode volume of 0.017$(\lambda_{vac}/n)^3$, and an optomechanical vacuum coupling rate of 310 kHz ismeasured. With optical quality factors up to $1.2 \cdot 10^5$, fabricateddevices are in the resolved-sideband regime. The electric field has its maximumat the slot wall and couples to the in-plane breathing motion of the slot. Theoptomechanical coupling is thus dominated by the moving-boundary effect, whichwe simulate to be six times greater than the photoelastic effect, in contrastto most structures, where the photoelastic effect is often the primary couplingmechanism.
展开▼
