基于氟化钙光学谐振腔的声传感机理研究

Research on acoustic sensing mechanism based oncalcium fluoride optical resonator

氟化钙回音壁模式谐振腔的光学品质因子实验上已经突破10^(11),同时能够实现高稳定棱镜耦合集成,因此,在非接触式的超高灵敏度声学传感方面具有重要的应用潜力。然而,对于高杨氏模量氟化钙晶体材料,外界声学扰动的机理尚不明确。基于氟化钙晶体盘型谐振腔结构,对外界声学扰动的影响机理进行研究。当外界声压作用于谐振腔时,从空气密度引起的折射率变化、弹光效应诱导有效折射率改变和谐振腔结构形变三个方面开展了研究。计算结果表明:声压导致的谐振腔结构形变影响最为明显,以实验室器件为参考,达到了1.196×10^(-10)Pa^(-1),对应的谐振峰波长响应为4.63×10^(-7)nm/Pa。谐振腔厚度及支撑结构的优化能够提升一个数量级以上,灵敏度可以较容易突破1 V/Pa。

The optical quality factor of the calcium fluoride(CaF_(2))whispering gallery mode resonator has exceeded 10^(11) experimentally.Meanwhile,it can realize the integration of high-stability prism coupling,so it has important application potential in non-contact ultra-high sensitivity acoustic sensing.However,for CaF_(2) crystal materials with high Young’s modulus,the mechanism of external acoustic disturbance is still unclear.The influence of external acoustic disturbance is studied based on the structure of CaF_(2) crystal disk-shaped resonator.When the external acoustic pressure acts on the resonator,the effect of air density,elastic-optic effect and structural deformation of the resonant cavity is studied.The results show that the effect of acoustic pressure on the deformation of the resonant cavity is the most obvious,which reaches 1.196×10^(-10) Pa^(-1),and the corresponding resonant wavelength response is 4.63×10^(-7) nm/Pa.The optimization of resonator thickness and support structure can improve one order of magnitude,and the sensitivity easily breaks through 1 V/Pa.