Device and method for measuring synchronous phase shifting interference of Fizeau quasi-common optical path structure

Abstract

The invention relates to a device and a method for measuring synchronous phase shifting interference of a Fizeau quasi-common optical path structure. The device comprises a laser, a half wave plate, a focusing lens, a spatial filter, a circularly polarized light beam splitter (an optically active crystal), a spectroscope, a collimating lens, a reference mirror, a pin-hole diaphragm, an imaging lens, a light splitting and phase shifting system, a computer control system and a CCD camera. According to the device and the method disclosed by the invention, a synchronous phase shifting technology is combined with a Fizeau interference method, so that technical difficulties of a conventional interferometer in poor stability and disability of realizing dynamic measurement are solved; the device and the method are characterized by utilizing an optical rotation effect of the crystal and adding the circularly polarized light beam splitter with a very small splitting angle in the Fizeau interfering structure, so as to realize orthogonally polarized separation of reference lights and test lights in a common optical path. The device and the method disclosed by the invention avoid utilization of a high-quality quarter wave plate in a synchronous phase-shifting interference system, and also greatly decrease a phase measurement error caused by a stress birefrigent effect which exists in an optical element of the system.

Description

technical field [0001] The invention belongs to the field of optical detection, and relates to an interferometry device and method, in particular to a Fizeau type synchronous phase-shift interferometry device and method. Background technique [0002] Interferometry technology is a recognized non-contact high-precision measurement method, which is widely used in a series of measurements involving the concept of optical path difference, such as surface shape detection of optical components, small deformation of materials, and uniformity of refractive index. Phase-Shifting Interferometry PSI (Phase-Shifting Interferometry) measurement technology was first proposed by Burning et al. Using digital wavefront phase detection technology, it realized high-precision, real-time and fast automated testing, greatly expanded the measurement function of the interferometer, and improved the test performance. Efficiency has promoted the improvement of modern optical manufacturing level. How...

AI Technical Summary

Problems solved by technology

[0005] The publication number of the Chinese patent "Synchronized Phase Shift Fizeau Interferometer for Real-time Measurement" is CN102580414A, and the publication date is August 2012. This patent uses a quarter-wave plate instead of a standard flat crystal to allow the object light and reference light to pass through Interference occurs after the common path, which can realize real-time measurement, but this method requires a high-quality quarter-wave plate, which is expensive, and it is not easy to realize the measurement of large-diameter spherical or aspheric

Images