Single-frequency laser interferometer nonlinear error correction method and device thereof

Abstract

A single-frequency laser interferometer nonlinear error correction method and a device thereof belong to the field of laser measurement technology. According to the method of the invention, under a precondition that the position of a first reflector and the position of a second reflector are unchanged, a liquid crystal phase delayer is used for generating a continuous light path difference changebetween a measuring light beam and a reference light beam, so that an enough phase change of an interference signal is generated, and pre-extraction for the characteristic parameter of the interference signal is realized, thereby correcting a nonlinear error in the displacement measurement process of the single-frequency laser interferometer by means of the pre-extracted characteristic parameter,and realizing high-precision displacement measurement. The single-frequency laser interferometer nonlinear error correction method and the device thereof realize pre-extraction for the characteristicparameter of the interference signal of the single-frequency laser interferometer and can effectively settle a problem of correcting the nonlinear error in interference measurement, particularly mini-displacement measurement. The method and the device thereof have substantial technical advantages in the precise measurement field.

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 polarization beam splitter that divides the single-frequency light source into a reference beam and a me...

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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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