频率扫描干涉仪漂移误差正反向扫描补偿法

Drift Error Compensation Method of Frequency Sweeping Interferometer by Consecutive Forward and Reverse Optical Frequency Scanning

频率扫描干涉仪对测量过程中光程差的漂移非常敏感,目标镜的微小位移会被放大几千倍,使得测量结果严重失真,因此必须消除或减弱漂移误差。针对现场测量中目标镜的低频振动或缓慢漂移,根据光频连续正反向扫描测量值漂移误差放大项大小近似相等、符号相反的特性,提出了一种光频连续正反向快速扫描的漂移误差补偿方法,并进行了频率扫描干涉仪漂移误差补偿实验,分析对比补偿前后的实验结果,验证了该方法的可行性。实验结果表明,在测量距离约1543.3mm处,目标镜振动频率为4.7Hz,振幅为1μm,采用补偿后,连续40次采样测量的标准差由补偿前的51.9μm下降到8μm。

Frequency sweeping interferometer is very sensitive to drift of optical path difference. Drift error is multiplied by an amplification factor to thousands of times, seriously affecting the measurement results, so it is necessary to remove or reduce drift error. For low-frequency vibration or slow drift of objective mirror under laboratory environment, the amplified drift errors of two consecutive forward and reverse scanning measurements are approximately equal in quantity but opposite in sign. According to these characteristics, a drift error compensation method by consecutive forward and reverse optical frequency scanning is proposed. Then, validation experiment is established to prove the feasibility of this method for vibration of objective mirror with frequency of 4.7 Hz and amplitude of 1μm. The experimental results show that the standard deviation of 40 measurements decreases from 51.9μm to 8 tim with distances up to 1543.3 mm, after applying this compensation method.