近红外谱域显微干涉仪的位移传感特性研究

Study of displacement sensing technology of near-infrared microscopic interferometry in spectral domain

为研究近红外谱域显微干涉仪在近红外波段的位移传感特性,分析了条纹载频对位移量提取的影响,建立了测量光谱中心波长与干涉仪位移传感范围之间关系公式,讨论了光源可见光分量对近红外光栅光谱仪所记录条纹的串扰现象并提出抑制方法。构建近红外迈克尔逊型谱域显微干涉实验系统,单次测量位移量传感精度优于0.02μm。测量标准台阶板的台阶高度(其标称值为7.732μm),测量偏差为0.044μm。采用近红外谱域显微干涉装置,无需轴向扫描即可实现位移量测量,将光谱仪记录的谱域干涉信号转换为随波数线性变化信号处理能有效提高位移传感精度,增大中心波长能够有效提高位移传感范围,在系统中加入短波截止滤光片则能有效抑制可见光分量对近红外光谱域条纹造成的串扰。

To research the technology of displacement sensing based on near-infrared microscopic interferometry in spectral domain, the impact of fringe carrier on extracting displacement is analyzed, the formula of spectral central wavelength and displacement range was deduced. Also the crosstalk of interference fringes caused by the visible light from illuminant recorded by the spectrometer was discussed. The near-infrared microscopic interference experiment system of Michelson type in the spectral domain is built up, the precision of displacement sensing at one time is 0.02 μm. The measured deviation of a standard step whose nominal value is 7.732 μm can reach 0.044 μm. No axial scanning was needed to realize displacement sensing with adopting device of near-infrared microscopic interference in the spectral domain. Through analyzing character of interference fringes in the near-infrared band, a conclusion that the accuracy of displacement sensing will enhance effectually can be drawn if the recorded fringes were transformed to fringes of displacement sensing was increased effectively by interference fringes caused by the visible light can linear cartier frequency for resolving, the range of enlarging the center wavelength, and the crosstalk of be restrained with a short-wave pass filter.