Double longitudinal-mode thermoelectric cooling frequency-offset-lock method and device based on iodine frequency stabilization reference

Abstract

A double longitudinal-mode thermoelectric cooling frequency-offset-lock method and a device based on the iodine frequency stabilization reference belong to the technical field of laser application; in the invention the center frequency of the iodine frequency stabilization laser with a relative frequency accuracy being 10<-11> is taken as a reference frequency, frequency locking is carried out on the frequency of the laser output by multi-double-longitudinal-mode lasers, therefore one fixed difference is maintained between the multi-lasers and the reference frequency, so that the relative frequency accuracy of the double-longitudinal-mode laser is improved from 10<-7>-10<-8> to 10<-9>, the frequency consistency of multi-double-longitudinal-mode lasers is improved from 10<-7> to 10<-9>, and meanwhile, a symmetrical thermal structure is preheated by a thermoelectric cooler and the cavity length of the frequency stabilization is regulated, thereby the influence of the radial distortion of a laser tube on the output frequency stability is eliminated, the environmental adaptability is enhanced, the preheating time is shortened and the service life of the laser tube is prolonged.

Description

technical field [0001] The invention belongs to the technical field of laser applications, in particular to a dual longitudinal mode thermoelectric cooling bias frequency locking method and device based on an iodine frequency stabilization reference. Background technique [0002] Laser interferometry technology is widely used in ultra-precision processing and measurement equipment industry due to its characteristics of non-contact, high precision, large measuring range, traceability, and multi-channel spectroscopic measurement. The accuracy of laser vacuum wavelength (laser frequency stability) determines It has become one of the core issues of fast ultra-precision laser interferometry technology to achieve the highest relative measurement uncertainty that the interferometry system can achieve. Under the impetus of the development of national defense equipment and microelectronics manufacturing industry for ultra-precision processing, laser The demand for relative measuremen...

AI Technical Summary

Problems solved by technology

However, the introduction of the auxiliary optical cavity leads to the complexity of the entire device structure, and the auxiliary optical cavity uses piezoelectric ceramic elements, which reduces the vibration resistance of the device

[0012] In summary, based on piezoceramic adjustment and locking in 127 I 2 Iodine frequency-stabilized lasers on ultra-fine absorption lines, although the relative accuracy of the center frequency is at or better than 10 -11 , and the consistency of the center frequencies of multiple iodine frequency-stabilized lasers reaches 10 -11 , but due to the shortcomings of low output power, poor anti-vibration performance, and high requirements for the working environment, it cannot be directly applied to industrial field measurements; the dual longitudinal mode frequency-stabilized laser based on electrothermal devices has a simple structure, but the warm-up time under different ambient temperatures The difference is large, and the higher preheating temperature brings the drift of the performance parameters of the photoelectric conversion device and other devices and the reduction of the life of the laser tube. The shortcomings of the frequency method, but its heat transfer structure has defects, it cannot uniformly heat or cool the laser tube, which affects the frequency stability of the laser, and the relative frequency accuracy is difficult to break through 10 -8 , and the frequency consistency between multiple dual longitudinal mode frequency stabilized lasers can only reach 10 -6 □10 -7 , in the case where multiple lasers need to be used for multi-dimensional synchronous measurement, this will bring the problems of wavelength reference, wavelength drift and spatial coordinate inconsistency, which will affect the comprehensive measurement accuracy of the interferometric system; bias frequency locking based on piezoelectric ceramics The relative accuracy of the frequency between the He-Ne laser and the dual longitudinal mode frequency-stabilized laser using iodine absorption frequency-stabilized technology reaches 10 -9 , but the structure is complex and the anti-vibration ability is poor, and the applicable occasions are strictly limited

It can be seen that the existing frequency-stabilized laser technology will be difficult to meet the requirements of the development of a new generation of ultra-precision processing and measurement technology

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