Simulation Study On The Coupling Effect In A Novel One-dimensional Hetero-optomechanical Crystal Nanobeam

Optomechanical crystal is a new kind of artificial periodic material which can modulate both electromagnetic and elastic waves,which is extensively used in the fabrication of acousto-optical micro-and nano-devices,and also has broad application prospects in the fields of cavity optomechanical and quantum information modulation.Compared with traditional sensors,optomechanical crystal sensors can realize the acousto-optical cross-detection of the object to be detected improve the detection accuracy and reduce the uncertainty.Therefore,how to achieve exceptional acousto-optical interaction through reasonable structural design and apply the optomechanical crystal to acousto-optical cross-detection to improve its sensing performance remain challenging research problems.The study primarily focuses on two fundamental basic issues problems,"The effect of heterostructure on the resonant cavities of the optomechanical crystal nanobeams"and"The effect of heterostructure on the acoustic-optical performance of optomechanical crystal sensor".For the effect of heterostructure on the acousto-optical interaction of optomechanical crystal nanobeam resonant cavities,two kinds of porous optomechanical crystal nanobeam resonant cavities are proposed in this dissertation.The energy distributions of electric and displacement for single mirror and hetero-optomechanical crystal nanobeam resonant cavities are calculated,and the factors affecting the optomechanical coupling rate are analyzed based on the moving interface effect and photoelastic effect.Results show that the single-mirror optomechanical crystal nanobeam resonant cavity exhibits phonon leakage in the mirror region,resulting in an optomechanical coupling rate of 3.68 MHz.Introducing the second mirror region to create heterostructure allows for separate constraints on acoustic and optical modes,thus improving phonon leakage.The optical quality factor,acoustic quality factor,and optomechanical coupling rate of the structure are enhanced to a certain extent,resulting in an optomechanical coupling rate of 3.81 MHz.To study the impact of heterostructure on the acoustic-optical performance of optomechanical sensors,an acoustic-optical sensor that can detect the concentration of solution was proposed.The effect of heterostructure on the acoustic-optical transmission spectrum introduced into the sensor was analyzed.Results demonstrate that the single-mirror optomechanical crystal sensor can detect different concentrations of glucose solution,calculated acoustic sensitivity of 3362 k Hz/ms^-1 and optical sensitivity of 177.78 nm/RIU.The introduction of heterostructure concentrates the acoustic and electric field energies more in the slits and holes of the defect region,enhancing the acoustic-optical sensitivity,acoustic-optical quality factor,and so on.The acoustic sensitivity of the sensor is 4389.09 k Hz/ms^-1,and the optical sensitivity is 200.42 nm/RIU.The findings of this investigation realizes the independent constraint of acoustic and optical modes by using two mirror regions,which provides a theoretical basics for the design of optomechanical crystal nanobeam resonant cavities with high optomechanical coupling rates and high quality factors.Furthermore,the introduction of heterostructure improves the acoustic-optical sensing performance of the optomechanical crystal sensor,providing a feasible method for the design of high-precision sensors.