Pore plate phase shift phase demodulation method for pinhole point diffraction interference measurement system

Abstract

The invention discloses a pore plate phase shift phase demodulation method for a pinhole point diffraction interference measurement system, which comprises the following steps of: converting linear polarization laser into circular polarization laser, expanding the circular polarization laser into parallel light, and converging the parallel light on a pinhole diffraction plate to be diffracted into detection wave and reference wave, wherein the detection wave is reflected to the pinhole diffraction plate through the detected aspherical mirror, reflected again by the pinhole diffraction plate and interfered with the reference wave, the pinhole diffraction plate is controlled to move by a corresponding step length in the direction of the optical axis of the detected aspherical mirror on the ZX plane, so the detection wave interferes with the reference wave to obtain an interference image of the corresponding step length, the interference image is collected, and a phase is obtained according to the acquired interference image information. According to the invention, the aperture of the measured mirror is prevented from being limited by the load capacity of the piezoelectric nano platform, and the measurable aperture range of the measured mirror is improved.

Description

technical field [0001] The invention belongs to the technical field of surface shape measurement by laser interferometry, and in particular relates to a method for phase shifting of an orifice plate used in a pinhole point diffraction interferometry system. Background technique [0002] The application of aspheric surfaces in optical systems can correct aberrations, improve image quality, reduce the number of system optical components, reduce weight and save space, etc. In recent years, it has gradually replaced spherical mirrors and has been more and more widely used. Especially in the fields of astronomical observation, military investigation and civilian high-tech, aspheric surfaces have become the most important components of many optoelectronic instruments. The existing aspheric surface polishing technologies are mainly plasma polishing and magnetorheological polishing, and the polishing resolution can be controlled at the nanometer level, while the limiting factor of t...

AI Technical Summary

Problems solved by technology

The common PZT method is widely used in the measurement of small-diameter aspheric surfaces, but it is difficult to achieve phase shifting for large-diameter aspheric surfaces due to its limited load capacity.

For point diffraction interferometry, it can guarantee high-precision detection, on the one hand because of its high-precision diffraction spherical wave, on the other hand because its optical path after the self-diffraction pinhole is very simple, except for the necessary in front of the CCD There are no other optical components outside the imaging device, and adding other devices will introduce additional errors

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