Nanometer measurement system based on synthetic interference signal polarization state detection technology

Abstract

The invention discloses a nanometer measurement system based on a synthetic interference signal polarization state detection technology. The system is composed of a laser interference unit and a polarization state detection unit. The laser interference unit introduces a polarization state conversion technology on the basis of a single-frequency Michelson interferometer to get synthetic linear polarized light containing displacement information. The polarization state detection unit is a polarization measurement system based on electro-optical liquid crystal phase modulation. The polarization state detection unit can detect the Stokes vector of emergent light of the laser interference unit, and obtain the ellipticity angle Epsilon and azimuth angle Theta of polarized light according to the Stokes vector. There is a linear relationship between the azimuth angle Theta and the displacement Delta(x) of a moving mirror. The azimuth angle Theta is measured with the help of a polarization state phase modulation technology. Thus, high-resolution phase subdivision is realized. By monitoring the ellipticity angle Epsilon and using a wave plate position adjustment method, the optical nonlinear error of the interferometer can be reduced. High-resolution and large-scale nanometer measurement is realized. Moreover, the system has an optical nonlinear self-correction function.

Description

technical field [0001] The invention relates to the technical field of precision measurement, in particular to a nanometer measurement system based on the polarization state detection technology of synthetic interference signals. Background technique [0002] Nano-displacement measurement technology is the core technology and key functional component of ultra-precision high-end manufacturing equipment such as high-end CNC machine tools, very large-scale integrated circuits, and large-area scanning probe microscopes. . At present, the main nano-measurement methods include scanning tunneling microscope, grating sensor and laser interferometer, etc., all of which can achieve sub-nanometer resolution. The measurement range of the scanning tunneling microscope is only in the micron range and there is a problem of meter traceability, and it is difficult to place the optical components of the grating sensor. Laser interferometer can realize large-scale nanometer measurement and s...

AI Technical Summary

Problems solved by technology

However, the measurement process of this method is a reduction process, and the real-time measurement is limited

Application publication number CN104697438A discloses a moving compensation type corner reflector laser interferometer and its use method. The interferometer obtains the fractional part of the interference wave in the interference process by setting a movable micro-movement platform to improve the accuracy, but it does not consider the optical Influence of Nonlinear Error on Measurement Accuracy

Images