Spatial phase-shifting unit, interferometry system applying same and phase-correcting unit

Abstract

The invention provides an interferometry system, which comprises a unit, a phase modulation type spatial light modulator, an interferometer and a light detector; the unit is used for generating mutually orthogonal linearly polarized lights in the polarized state, and the mutually orthogonal linearly polarized lights are respectively called reference light and testing light; the phase modulation type spatial light modulator is arranged in the light path of the reference light or the testing light, and is used for changing spatial phase distribution before light waves; the spatial light modulator is provided with a plurality of pixels, each of which has specific phase distribution; the light, the phase of which is modulated by the spatial light modulator, is called modulated light, and the light which is not modulated is called unmodulated light; the interferometer is based on the modulated light and the unmodulated light to carry out interferometry; the coherent light generated by the interferometer is detected by the light detector; and moreover, the pixels of the spatial light modulator are corresponding to the pixels of the light detector. The system provided by the invention not only can carry out measurement during the phase shift distribution of a plurality of spatial carriers, but also can carry out high-precision dynamic measurement. The invention also provides a spatial phase-shifting unit and a liquid crystal spatial light modulator phase-correcting unit.

Description

technical field [0001] The invention relates to the technical field of optical detection, in particular to a spatial phase shift device. The invention also provides a phase correction device and an interferometric measurement device using the space phase shifting device. Background technique [0002] Interferometer has important application value in the surface shape detection of optical components. As far as the interferometry method is concerned, it can be divided into time-domain phase shift method, Fourier analysis method and space carrier phase shift method. The time-domain phase shift method has high measurement accuracy and is widely used in optical detection, but it requires at least three interferograms and is greatly affected by environmental vibrations, so it is not suitable for measurement in dynamic environments. The Fourier analysis method only needs a space carrier interferogram, so it is suitable for measurement in a dynamic environment, but the measurement...

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Problems solved by technology

[0004] Although the above-mentioned polarization phase mask can introduce space carrier phase shift, its processing is more difficult, it is easy to produce processing errors, and it is not easy to correct processing errors, and processing errors will directly affect the accuracy of interferometric measurements. Therefore, the polarization The accuracy of the phase mask needs to be further improved; in addition, a processed polarization phase mask can only produce a specific spatial carrier phase shift distribution, which cannot be artificially modified, and its application will inevitably be limited

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