Low non-linear error and low temperature drift two-frequency laser interference device

Abstract

The invention provides a low non-linear error and low temperature drift two-frequency laser interference device, comprising a first polarization splitting prism, a second polarization splitting prism located on a light path of transmitted light of the first polarization splitting prism; a third polarization splitting prism located on a light path of transmitted light of the first polarization splitting prism; a first quarter-wave plate, the second polarization splitting prism located between the first quarter-wave plate and the first polarization splitting prism; at least a first prism of corner cube deposited in parallel to one side of the second polarization splitting prism; a second quarter-wave plate located one end of the third polarization splitting prism. The invention uses a plurality of polarization splitting prisms cascaded and path length in the interference device of measuring light path and reference light path. Therefore the device has low non-linear error and low temperature drift.

Description

technical field [0001] The invention relates to the field of high-precision displacement measurement, and in particular to a low-nonlinear error and low-temperature drift dual-frequency laser interference device and method. Background technique [0002] Interference fringes are generated when coherent light meets different paths in space. By demodulating the interference fringes, the optical path difference change of one path of light relative to the other path of light can be measured, thereby measuring the tiny displacement of the object. The dual-frequency laser interferometer uses the laser wavelength as the measurement scale, and through optical subdivision and electronic subdivision, the measurement can achieve high precision. And it has the advantages of large range and high speed. Therefore, it is widely used in microelectronics manufacturing, precision machine tools, automobile industry, aerospace and other fields. [0003] However, with the continuous improvement...

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Problems solved by technology

[0009] The above is the introduction of the optical path in the prior art. The current general-purpose polarization beam splitter prism has relatively low light splitting performance.

The low-temperature drift dual-frequency laser interference device composed of it has relatively low temperature drift, but the nonlinear error is still relatively large, which cannot meet the needs of ultra-precision sub-nanometer displacement measurement

If the extinction ratio of the polarization beam splitter prism is increased, higher performance coating equipment and detection equipment are required, and the cost is high

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