Dual-frequency laser ranging method and device based on polarization state regulation and wavelength synthesis

Abstract

A dual-frequency laser ranging method and a device based on polarization state regulation and wavelength synthesis belong to the technical field of laser application. In absolute distance measurement and relative displacement measurement, the method adopts the same frequency stabilized laser as a measuring light source, realizes organic integration of absolute distance measurement and relative displacement dynamic measurement through the control of a polarization rotator and wavelength tuning of acoustooptic frequency shifters and simultaneously meets the requirements on extra long distance precise measurement and fast local displacement ultraprecise monitoring. The device comprises an acoustooptic frequency shifter A and an acoustooptic frequency shifter B, a reflecting mirror A and a reflecting mirror B, a frequency control unit A and a frequency control unit B, a polarization rotator, a polarization splitter B and a laser wavelength split and synthesis unit formed by partial optical splitters. The invention has the advantages of both extra long distance ultraprecise measurement capability and integral formation, etc.

Description

technical field [0001] The invention belongs to the technical field of laser applications, in particular to a dual-frequency laser ranging method and device based on polarization state regulation and wavelength synthesis. Background technique [0002] The dual-frequency laser interferometer is suitable for low-speed and quasi-static local displacement measurement occasions, but cannot meet the needs of ultra-large-scale precision measurement and local displacement fast ultra-precise real-time monitoring occasions. The HP5527 series of Hewlett-Packard Company of the United States and the ZMI series of dual-frequency laser interferometers of ZYGO Company are used for ultra-precise measurement of relative displacement. When measuring the length of this laser measurement system, a guide rail along the measurement direction must be used to make the laser interferometer in some The application in occasions is limited, and its displacement measurement range generally does not excee...

AI Technical Summary

Problems solved by technology

The my country-made dual-frequency laser interferometer prototype was developed by the Chinese Academy of Metrology and Shaanxi Institute of Mechanical Engineering. The relative displacement measurement range is 60m, and the measurement accuracy is 0.5×10 -6 , Chengdu Tool Research Institute also produced a dual-frequency laser interferometer equipped with a device for compensating air state parameters, but both are only suitable for static and quasi-static measurement occasions, and cannot complete fast ultra-precise displacement monitoring or absolute distance measurement

[0003] In order to solve the problem of absolute distance measurement, American API, Faro and Swiss Leica companies have developed laser trackers, which can realize precise measurement of absolute distance and relative displacement within 60m without any guide rail, but the accuracy of relative displacement measurement is generally only It reaches the order of μm, and its displacement measurement speed is 1KHz, which cannot realize real real-time measurement

In absolute distance interferometry, the synthetic wavelength method is one of the commonly used methods. The light source used in it must be able to emit two or more stable wavelengths at the same time, usually through one or more lasers. Due to the use of multi-wavelength lasers or Multiple single-wavelength lasers are used as light sources, and the wavelength interval is a fixed value. Only some fixed synthetic wavelengths can be obtained. In order to obtain a suitable synthetic wavelength, increasing the number of lasers will make the system more complicated. Multiple lasers emit beams at the same time. Shaft is not easy to guarantee

Patent DE 19522262 describes a system with two laser light sources to generate the synthesized wavelength, although the structural stability of the interferometer and the stability of the target distance are not high, the system structure is complex

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