A Nanoscale Photonic Crystal Cavity Optomechanical System for Ultrasensitive Motion Sensing

Optomechanical nanocavities open a new hybrid platform such that the interaction between an optical cavity and mechanical oscillator can be achieved on nanophotonic scale. Owing to attractive advantages as ultrasmall mass, high quality, small mode volume flexible mechanics, pair of coupled photonic crystal nanobeam (PCN) cavities are utilized in this paper establish optomechanical nanosystem, thus enabling strong coupling effects. In PCN cavities, one with mass meff~3 pg works in-plane movable at fundamental frequency πΩm/2π=4.148 MHz. The other couples light excite supermodes 1542.858 1554.464 nm Qo larger than 4 × 104. Because backaction arising from force, abundant phenomena unresolved sideband observed nanobeam. Moreover, benefiting movement nanobeam, we maximum displacement 1468 fm/Hz1/2. These characteristics indicate nanocavity is capable ultrasensitive motion measurements.