Longitudinal Zeeman laser frequency locking method and apparatus based on piezoelectric effect and acousto-optic frequency shift

Abstract

A longitudinal Zeeman laser frequency locking method and apparatus based on piezoelectric effect and acousto-optic frequency shift belong to the technical field of laser application. The method employs the acousto-optic frequency shift technology to lock the output laser frequency of a plurality of longitudinal Zeeman lasers based on cavity length piezoelectric adjustment onto the output laser frequency of a reference longitudinal Zeeman frequency-stabilized laser, so that laser output by all the lasers has a unified frequency value. The method aims to solve the defect that frequency-stabilized lasers in the prior art are low in consistency of frequency and provides a novel laser source for ultra-precision laser interference measurement.

Description

technical field [0001] The invention belongs to the field of laser application technology, in particular to a longitudinal Zeeman laser frequency locking method and device based on piezoelectric effect and acousto-optic frequency shifting. Background technique [0002] In recent years, ultra-precision measurement and processing technologies represented by lithography machines and CNC machine tools have developed towards large-scale, high-precision, multi-space degrees of freedom simultaneous measurement, and the total laser power consumption of the laser interferometry system has increased sharply. The output laser power exceeds the output laser power of a single frequency-stabilized laser, so it is necessary to use multiple frequency-stabilized lasers for combined measurement at the same time. However, there are differences in the relative frequency stability, laser wavelength value, and wavelength drift direction of different frequency-stabilized lasers, which will bring a...

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Problems solved by technology

[0003] The frequency-stabilized laser sources currently used in laser interferometry systems mainly include dual-longitudinal-mode frequency-stabilized lasers, transverse Zeeman frequency-stabilized lasers, and longitudinal Zeeman lasers. The center frequency of the laser gain curve is used as the frequency stabilization reference for such lasers. The reference frequency of frequency stabilization control, while the center frequency of the laser gain curve changes with the working gas pressure and discharge conditions, and the physical parameters of multiple frequency stabilization lasers cannot be highly consistent, so there are differences in the reference frequency of frequency stabilization control , resulting in low frequency consistency of laser output from multiple frequency-stabilized lasers, which can only reach 10 -6 ~10 -7

[0004] In order to solve the problem of poor frequency consistency between frequency-stabilized lasers, Harbin Institute of Technology proposed a dual longitudinal mode laser bias frequency locking method (Chinese Patent Application Nos. The output laser frequency of the frequency-stabilized laser or the dual longitudinal mode laser is used as a reference, and the remaining multiple dual longitudinal mode lasers are locked by a certain value relative to the reference frequency, so that the output lasers of multiple dual longitudinal mode lasers have the same wavelength ( frequency), but this method needs to adjust the internal working parameters of the laser during the laser frequency locking process. On the one hand, because the adjustment method is an indirect adjustment, the response speed of the system is relatively slow. On the other hand, due to the characteristic parameters of each laser There are certain differences, and changes in the internal working parameters of the laser may have a negative impact on the frequency stability of the laser, and in severe cases it may even cause the laser to lose lock

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