以慢变化近似为基础的新型正弦相位调制半导体激光干涉仪

A Novel Sinusoidal Phase Modulating Laser Diode Interferometer Based on Slowly Varying Approximation

提出并在实验上实现了一种以慢变化近似为基础的新型正弦相位调制半导体激光（ＳＰＭ－ＬＤ）干涉仪。原理上它不要求相位解调一次和二次谐波分量振幅在实验中必须保持相等，从而将动态范围提高了３～４个数量级且不损失精度。用压电陶瓷和微电机驱动位移。当压电陶瓷驱动位移大于半波长时，均方根误差为５ｎｍ。测量所得到的最大位移为１ｍｍ。系统能在噪声环境中进行自动实时位移测量。

A novel sinusoidal phase modulating laser diode interferometer based on slowly varying approximation is proposed and demostrated. It is not necessary in principle to keep amplitutes of the first and second harmonic components equal in expriment, and dynamic range has been inrceased 3￣4 order. A PZT and Picomotor are used as displacement actuator to detect the resolution (or accuracy) and dynamic range. The accuracy is 5 nm when the displacement drived by PZT exceeds a half wavelength of the light. The maxmum displacement measured is more than 1 mm. This system can complete real time and auto measurement under noise circumstance.