A device for detecting object surface shape based on vortex optical helical phase shift interference

Abstract

The invention discloses a device for detecting object surface shape based on vortex optical helical phase shift interference. After the light emitted by the laser is beam expanded and collimated and two polarizers are used, a Taiman Green system is used at the beam splitting prism. The beam is modulated by the beam expander lens group to the spatial light modulator and emitted to generate a vortex beam as a reference light. The other beam passes through the measured transparent object and is reflected by a standard reflector, or directly reflected by the measuring surface object, and the reference light The beams are combined at the beam splitting prism to form an interference pattern on the receiving surface of the photoelectric sensor; the surface shape of the object is calculated by using the phase formula; the present invention uses the Taiman Green system to make the spatial light modulator perpendicular to the optical axis, and the spatial light modulator at this angle The diffraction efficiency reaches the maximum, and the interference effect of the generated vortex light and object light is of good quality. The invention combines the vortex light with the Taiman Green system, has a simple structure, is easy to operate, and has more precise phase shift, which is a great improvement compared with the current technology.

Description

technical field [0001] The invention belongs to the technical field of optical detection, and in particular relates to a device for detecting object surface shape based on vortex optical helical phase shift interference. Background technique [0002] The vortex beam is a new type of beam, which has a spiral wavefront structure and each photon carries orbital angular momentum. The beam center of the vortex beam has a phase singularity, so that the light intensity of its cross section is distributed in a ring-shaped hollow. Common vortex beams include Laguerre-Gaussian beams, Bessel beams, etc. Since the vortex beam has a spiral phase, its phase distribution is a spiral [0,2π] distribution, so the phase shift can be realized by designing the phase rotation angle of the vortex light, so that the two-dimensional surface shape of the object can be detected by phase shift interferometry. Spatial light modulator is widely used as a phase shift device as a method that can avoid me...

AI Technical Summary

Problems solved by technology

Spatial light modulator is widely used as a phase shift device as a method that can avoid mechanical movement and change its phase shift amount in a very short time, but the actual measured phase value of this method is always within a Fluctuations in a small range will have a certain impact on the measurement accuracy

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