High-speed single-photoelastic modulated interferometer with large optical path difference

The utility model relates to a spectrograph and provides a novel single-photoelastic modulated interferometer which is high in spectral resolution, high in modulation speed and free of mechanical motion, simultaneously can ensure enough luminous flux and is used for substituting for the traditional Michelson interferometer. According to the technical scheme, the novel single-photoelastic modulated interferometer is composed of a polarizer, a static-state birefringent crystal, a first lens, a photoelastic modulator, a polarization analyzer, a second lens and a detector which are sequentially arranged along the incident direction of detected light. The light passing direction of the static-state birefringent crystal is an optical axis direction of the crystal. The photoelastic modulator comprises a piezoelectric driver and a photoelastic crystal, wherein the photoelastic crystal is octangle, and the front and rear light passing surfaces are spherical surfaces and are plated with high-reflectance films which are staggered mutually.