Fizeau double-wavelength interference test device and synthetic wavelength phase extraction method thereof

The invention discloses a Fizeau double-wavelength interference test device and a synthetic wavelength phase extraction method thereof. During work under two wavelengths, a dichroic mirror is used to collect a single-wavelength phase-shifting interferogram. Work under two wavelengths can be realized by only eliminating the chromatic aberration of part of optical paths. Then, in view of the problem in the traditional double-wavelength phase-shifting interference test device that phase shifting error under different wavelengths is caused by PZT phase shifting, a way of synthetic wavelength-single wavelength phase processing is used to suppress the influence of phase shifting error under different wavelengths on synthetic wavelength phase and avoid calibration of phase-shifting step amount under two wavelengths. The method can also be used to effectively measure the vibration and multiple-beam interference errors under different wavelengths. As there is only the need to control the test precision under a single wavelength, synthetic wavelength phase data can be extracted quickly and easily by use of the method.