Abstract
Optomechanical nanocavities open a new hybrid platform such that the interaction between an optical cavity and mechanical oscillator can be achieved on a nanophotonic scale. Owing to attractive advantages such as ultrasmall mass, high optical quality, small mode volume and flexible mechanics, a pair of coupled photonic crystal nanobeam (PCN) cavities are utilized in this paper to establish an optomechanical nanosystem, thus enabling strong optomechanical coupling effects. In coupled PCN cavities, one nanobeam with a mass meff~3 pg works as an in-plane movable mechanical oscillator at a fundamental frequency of πΩm/2π=4.148 MHz. The other nanobeam couples light to excite optical fundamental supermodes at 1542.858 and 1554.464 nm with a Qo larger than 4 × 104. Because of the optomechanical backaction arising from an optical force, abundant optomechanical phenomena in the unresolved sideband are observed in the movable nanobeam. Moreover, benefiting from the in-plane movement of the flexible nanobeam, we achieved a maximum displacement of the movable nanobeam as 1468 fm/Hz1/2. These characteristics indicate that this optomechanical nanocavity is capable of ultrasensitive motion measurements.
Highlights
Cavity optomechanical systems, which integrate mechanical oscillators with optical cavities into micro-/nanoscale photonic devices, have reinforced the interaction between optical modes and mechanical modes to an unprecedented level [1,2]
Optomechanical systems established on photonic platforms include Fabry–Perot (F–P) cavities [15], whispering gallery mode (WGM) cavities [16] and photonic crystal (PhC) cavities
This mode competition resulted in the significant amplification of mechanical oscillation and contributed to a bistable optomechanical system. Inspired by these optomechanical effects and sensing characteristics in the coupled photonic crystal nanobeam (PCN) cavities, in this paper, an optomechanical nanocavity consisting of two PCNs is proposed with high optomechanical coupling strength and large optical-force-driven displacement. In this coupled PCN cavity, one of the PCNs is cut off to obtain a flexible nanobeam acting as a movable mechanical oscillator; the other fixed nanobeam is contacted with a dimpled fiber taper to excite the optical mode
Summary
Cavity optomechanical systems, which integrate mechanical oscillators with optical cavities into micro-/nanoscale photonic devices, have reinforced the interaction between optical modes and mechanical modes to an unprecedented level [1,2]. This mode competition resulted in the significant amplification of mechanical oscillation and contributed to a bistable optomechanical system Inspired by these optomechanical effects and sensing characteristics in the coupled PCN cavities, in this paper, an optomechanical nanocavity consisting of two PCNs is proposed with high optomechanical coupling strength and large optical-force-driven displacement. In this coupled PCN cavity, one of the PCNs is cut off to obtain a flexible nanobeam acting as a movable mechanical oscillator; the other fixed nanobeam is contacted with a dimpled fiber taper to excite the optical mode. Noise analysis is performed on the optomechanical system to evaluate the sensitivity of displacement
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have