Single-beam three-degree-of-freedom heterodyne laser interferometer based on array detector

Abstract

The invention discloses a single-beam three-degree-of-freedom heterodyne laser interferometer based on an array detector, and belongs to the technical field of laser application. According to the invention, two coaxially transmitted laser beams with different frequencies are input to the Michelson interference structure, the angle of the reference plane mirror is set to enable the measurement beam and the reference beam to perform non-coaxial interference and form a single-beam heterodyne interference signal, and the array detector is selected to effectively receive the single-beam heterodyne interference signal. Finally, three-degree-of-freedom signal linear decoupling on the single-beam heterodyne interference signal is achieved through a three-degree-of-freedom decoupling method. The laser interferometer does not have angle decoupling nonlinearity, the period nonlinear error is remarkably reduced, compared with other existing three-degree-of-freedom laser interferometers, the laser interferometer has the advantages of being simple in structure, large in angle measurement range and easy to integrate, and the high-precision requirement of the three-degree-of-freedom laser interferometer for displacement and angle measurement is met.

Description

technical field [0001] The invention belongs to the technical field of laser applications, and mainly relates to a single-beam three-degree-of-freedom heterodyne laser interferometer based on an array detector. Background technique [0002] Laser interferometry technology is the basic core technology in precision engineering, and plays a very important role in the fields of precision measurement, high-end equipment manufacturing and large scientific devices. With the rapid development of the above fields in recent years, not only the accuracy of displacement measurement needs to be improved from nanometer level to sub-nanometer or even picometer level, but also the form of displacement measurement needs to be changed from single-axis displacement measurement to multi-axis / angular displacement three-dimensional Composite measure of degrees of freedom. [0003] At present, the most widely used in the field of multi-axis laser interferometry is the laser interferometer based o...

AI Technical Summary

Problems solved by technology

The representative one is the compact differential wavefront interferometer (Yu X., Gillmer S.R., Ellis J.D. Beam Geometry, Alignment, and Wavefront Aberration Effects on Interferometric Differential Wavefront Sensing [J]. Measurement Science and Technology ,2015,26(12):125203), but the differential wavefront interferometer has the principle error of angle decoupling nonlinearity and directly limits the angle measurement accuracy and angle measurement range, resulting in its angle measurement range being larger than that of traditional heterodyne laser interferometry The instrument is smaller, usually in the order of 0.1mrad or below

[0007] In summary, the existing laser interferometer based on parallel beam measurement has the problems of complex structure, extremely difficult processing and multi-axis periodic nonlinear coupling. The differential wavefront interferometer for single-beam measurement has the problems of angular coupling nonlinearity and small angular measurement range, which seriously limits the improvement of the three-degree-of-freedom measurement capability of laser interferometers

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