Nonlinear error correction method and device for single-frequency laser interferometer

Abstract

The invention relates to a nonlinear error correction method and device for a single-frequency laser interferometer and belongs to the field of laser measurement technologies. According to the nonlinear error correction method and device for the single-frequency laser interferometer of the invention, under a premise that the positions of a first reflector and a second reflector are changed, the continuous optical path difference change of a spiral phase plate generated between a measuring beam and a reference beam is utilized, so that interference signals can generate sufficient phase change,and therefore, the pre-extraction of the characteristic parameters of the interference signals is realized; and the pre-extracted characteristic parameters can be utilized to correct the nonlinear error of the single-frequency laser interferometer in a displacement measurement process, and high-precision displacement measurement can be realized. With the nonlinear error correction method and device for the single-frequency laser interferometer of the invention adopted, the pre-extraction of the characteristic parameters of the interference signals of the single-frequency laser interferometer is realized, and the correction problem of the nonlinear error in interferometric measurement, especially micro-displacement measurement can be solved. The nonlinear error correction method and devicehave significant technical advantages in the field of precision measurement.

Description

technical field [0001] The invention belongs to the technical field of laser measurement, and mainly relates to a method and device for correcting nonlinear errors of a single-frequency laser interferometer. Background technique [0002] With the rapid development of scientific research and the rapid improvement of industrial production levels, scientific research and industrial fields have also put forward higher requirements for displacement measurement, and the minimum change of displacement measurement is also developing towards the nanometer level. Single-frequency laser interferometry is an instrument for high-precision displacement measurement using the principle of laser interferometry. It has the advantages of non-contact and high precision. A single-frequency laser interferometer includes at least one light source capable of providing a single-frequency laser; a beam splitter that divides the single-frequency light source into a reference beam and a measurement bea...

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Problems solved by technology

But this method also has certain problems: additional motion control components increase the complexity of the system and control, and inevitably affect the position stability of the first mirror, thus introducing measurement errors

However, this method also has certain defects: first, this method can only obtain the DC offset error and unequal amplitude error parameters in the triple difference of the characteristic parameters of the interference signal, but cannot obtain the non-orthogonal error parameters, so it is necessary to Measurement can only be carried out with a specific interference optical path structure, which is not universal; secondly, this method requires two optical switches, which leads to an increase in the size of the device, and requires multiple operations on the two optical switches, and the steps are complicated

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