Eliminating method of system errors in raster shearing interferometer wave aberration detecting

Abstract

Provided is an eliminating method of system errors in raster shearing interferometer wave aberration detecting. According to the method, + / - one-level diffraction light is used for carrying out shearing interferometry with zero-level diffraction light respectively, difference information is subjected to wave-front reconstruction and turning processing, relevant parameters, namely the space distance of rendezvous points of diffraction light of different levels and the inclination angle of a detector of main system error terms which affect raster shearing interferometer wave aberration detecting accuracy are obtained by numerical calculation, geometry optical-distance errors and detector inclination errors in wave aberration detecting are eliminated, and wave aberration detecting accuracy is improved. The geometry optical-distance errors and the detector inclination errors in wave-front reconstruction are eliminated according to practical situations, and the accuracy of raster shearing interferometer wave aberration detecting is improved.

Description

technical field [0001] The invention relates to a grating shearing interferometer, in particular to a method for eliminating systematic errors in wave aberration detection of the grating shearing interferometer. Background technique [0002] Grating shearing interferometer is an important form of wavefront sensor, which has the advantages of simple structure, no need for a separate reference wavefront, easy to achieve common optical path interference, and anti-environmental interference. The grating shearing interferometer has systematic errors such as geometric optical path error, grating diffraction error, grating position offset, and detector tilt, which affect the detection accuracy of wave aberration; especially for the application of high-precision optical system wave aberration detection, the test The optical system has a certain numerical aperture (NA), and the difficulty of system alignment and systematic error increase with the numerical aperture. The wave aberrati...

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Problems solved by technology

Although the above methods can improve the detection accuracy to a certain extent, due to the difficulty of grating positioning and system alignment, and the geometric optical path error still exists, or the method of theoretical calculation based on pre-measured corresponding data, the data obtained from the experiment Subtracting the theoretical geometric optical path error, the geometric optical path error has not been eliminated according to the actual parameters, the residual geometric optical path error and detector tilt error are relatively large, or auxiliary means need to be used to eliminate the detector tilt error, increasing Wave aberration detection difficulty

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