Differential single-frequency interference signal processing device and method with integrated four-quadrant photoelectric detector

Abstract

The invention discloses a differential single-frequency interference signal processing device and method with an integrated four-quadrant photoelectric detector. The processing device comprises an interference unit and detection unit; and a photoelectric phase modulator is added to a reference arm. The detection unit consists of a quarter-wave plate, a polarizer piece, a beam expander and an integrated four-quadrant photoelectric detector and is used for detecting interferometric fringes of a measuring beam and a reference beam and generating four paths of interference signals. The photoelectric phase modulator applies a high-frequency sine wave modulation voltage, so that the interference signal becomes a phase generation carrier interference signal including to-be-tested phase information. PGC demodulation is carried out to obtain four groups of orthogonal signals; calculation is carried out to obtain four paths of interference signal phases; and a differential phase change is calculated to measure the displacement, a deflection angle and a pitch angle and compensation is carried out. According to the invention, the non-linear error of the measuring method is reduced; the light intensity interference influence caused by poor performances of an optical element or a mounting error is eliminated; the phase measurement accuracy and stability are improved; the angle measurement precision and the measuring range are increased; and the measurement accuracy of the displacement is improved.

Description

technical field [0001] The invention relates to a metering device and method characterized by adopting an optical method, in particular to a differential single-frequency interference signal processing device and method using integrated four photodetectors. Background technique [0002] Laser single-frequency interferometer has the advantages of high measurement accuracy, high sensitivity, good stability and large measurement range, and is widely used in the field of ultra-precision measurement. However, in the actual displacement measurement process, it is unavoidable to be affected by the misalignment of the beam caused by the lateral offset and inclination of the measured object. Single-frequency interferometers usually use methods such as quadrature detection and phase-generated carrier (PGC) single-frequency phase detection to detect phases. Although these phase detection methods have their own advantages, they cannot compensate for the inclination of the measured objec...

AI Technical Summary

Problems solved by technology

At present, the differential wavefront sensing method is applied to the heterodyne interferometer, but it has the nonlinear effect of the milliarc level, and the beam shearing will also affect the nonlinearity of the differential wavefront sensing method.

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