Abstract:
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 m. The measured deviation of a standard step whose nominal value is 7.732 m can reach 0.044 m. 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 linear carrier frequency for resolving, the range of displacement sensing was increased effectively by enlarging the center wavelength, and the crosstalk of interference fringes caused by the visible light can be restrained with a short-wave pass filter.