Double-longitudinal-mode laser composite frequency stabilization method and device based on thermoelectric cooler

Abstract

A double-longitudinal-mode laser composite frequency stabilization method and a device based on a thermoelectric cooler belong to the technical field of laser application; the invention proposes a thermoelectric cooler-based double-longitudinal-mode laser composite frequency stabilization method, a laser of the double-longitudinal-mode laser comprises two working modes of a frequency stabilization mode and a frequency locking mode and takes a thermoelectric cooler as a temperature controlling actuator; when the frequency stabilization mode is adopted, A control system takes the power difference of two longitudinal mode light of the laser as a feedback signal, when the frequency locking mode is adopted, the control system takes the frequency difference of a laser output beam and an external high stable reference beam as a feedback signal, and realizes the frequency stabilization of the laser according to the control algorithm; and improves the relative frequency stability of the double-longitudinal-mode laser from 10<-7>-10<-8> to 10<-9>, thus enhancing environmental adaptability of the laser, and greatly expanding application range of the laser.

Description

technical field [0001] The invention belongs to the field of laser application technology, in particular to a dual longitudinal mode laser composite frequency stabilization method and device based on a thermoelectric cooler Background technique [0002] One of the characteristics of laser is good monochromaticity, the laser line width limit caused by spontaneous radiation noise is very small, but due to the influence of various unstable factors, the optical frequency drift of the free-running laser is far greater than the line width limit, and its relative The frequency accuracy is only 10 -5 ~10 -6 . With the continuous development of science and technology, the ultra-precision measurement and processing industry has put forward higher and higher requirements for the frequency accuracy of lasers. At present, ultra-precision processing generally requires the relative accuracy of laser frequency to reach 10 -7 ~10 -8 , some special occasions, such as lithography machine a...

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Problems solved by technology

However, this method only heats or cools one side of the laser tube, so that the laser tube is heated unevenly, which causes the resonator mirror of the laser tube to tilt and affects the frequency stabilization effect of the laser.

[0009] In summary, although the relative accuracy of the center frequency of the iodine-stabilized laser reaches or is better than 10 -11 , but due to the shortcomings of poor anti-vibration performance, high price, and high requirements for the working environment, it cannot be directly applied to on-site measurement of ultra-precision measurement and processing; the relative accuracy of the frequency of Lamb's concave frequency-stabilized laser can reach 10 -9 , but its anti-vibration performance is also poor, so it cannot be used in field applications of ultra-precision measurement and processing

The frequency relative accuracy of dual longitudinal mode frequency stabilized laser and Zeeman frequency stabilized laser can reach 10 -7 □10 -8 , but difficult to exceed 10 -8 , unable to meet the requirements of special occasions for ultra-precision machining and measurement; it can be seen that the existing frequency-stabilized lasers are difficult to be widely used in various industrial production occasions of ultra-precision machining and measurement

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