弹光调制器中硒化锌弹光晶体谐振频率的测量

Measurement of resonant frequency of ZnSe crystal in photo-elastic modulator

针对弹光调制器(PEM)中石英驱动器和硒化锌晶体的谐振频率匹配不精确的问题,建立石英驱动器单自由度振动模型和石英驱动器-硒化锌晶体双自由度振动模型,推导各自的幅度-频率和相位-频率关系,提出根据幅度-频率和相位-频率曲线,通过曲线拟合求解谐振频率和其他参数的方法。依据实验测试所得数据,应用1st Opt对石英驱动器和石英驱动器-硒化锌晶体分别做了幅度-频率和相位-频率曲线拟合,结果表明,拟合得到的硒化锌Q值与标准Q值的误差仅为3.8%,较为准确地测得了硒化锌的谐振频率。

In order to solve the inaccurate matching of the resonant frequency of quartz driver with Zn Se crystal in photoelastic modulator（ PEM）,a single-freedom model of quartz driver and a dual-freedom model of quartz driver- Zn Se crystal are built based on mechanic vibration theory. The amplitude- frequency and the phase- frequency relationships of the two models are deduced. A method of solving the resonant frequency and other parameters based on amplitude- frequency curve and phase- frequency curve are presented according to curve fitting. The two curves of quartz driver and quartz driver- Zn Se crystal are fitted by 1st Opt software with test data.The result shows that,compared with standard Q value,the fitting error value of Zn Se crystal is only 3. 8%,which indicates the resonant frequency of Zn Se crystal is more accurately measured.