Femtosecond laser absolute distance measuring device and method based on non-linear optical sampling

Abstract

The invention provides a femtosecond laser absolute distance measuring device based on non-linear optical sampling. The femtosecond laser absolute distance measuring device comprises two femtosecond laser frequency combs with different repetition frequencies, a Michelson interference distance measuring device, a second kind phase matching non-linear optical frequency multiplication structure and a data acquisition and processing unit. The two femtosecond laser frequency combs with the different repetition frequencies are used for achieving optical scanning on a time domain. The second kind phase matching non-linear optical frequency multiplication structure is used for generating frequency multiplication light when input pulses coincide in the time domain. The data acquisition and processing unit is used for detecting frequency multiplication optical signals, conducting calculus of differences on collected data, extracting the sequence number of a zero crossing point in the data after the difference in an array, and calculating the length difference of a reference arm and a measuring arm. The invention further provides a measuring method using the femtosecond laser absolute distance measuring device. According to the femtosecond laser absolute distance measuring device and method based on non-linear optical sampling, the off-set frequency does not need to be locked, absolute distance measuring of a continuous range based on a time-of-flight method is achieved, and therefore the applied field of femtosecond laser absolute distance measuring is widened.

Description

technical field [0001] The invention belongs to the field of femtosecond laser distance measurement, in particular to a femtosecond laser absolute distance measurement device and method based on nonlinear optical sampling. Background technique [0002] Due to the high degeneracy of photons, laser has many advantages such as good directionality and long coherence length, and plays an important role in mechanical manufacturing, space remote sensing, satellite formation flight and distance measurement. An optical frequency comb is a wide-spectrum coherent laser source developed on the basis of a mode-locked laser, and its longitudinal modes can be traced to a frequency reference. Taking advantage of the traceability of its frequency, countries such as the United States, the Netherlands, Germany, and South Korea have successively carried out high-precision absolute distance measurement based on optical frequency combs. In 2004, American physicist J.Ye proposed to use the time-d...

AI Technical Summary

Problems solved by technology

The disadvantage of this experimental scheme is that the length to be measured is limited by the adjustment range of the repetition frequency of the optical frequency comb, and only certain discrete specific lengths can be measured, and continuous absolute distance measurement cannot be achieved.

The disadvantage of this solution is that the measurement principle is based on linear optical sampling, the repetition frequency and bias frequency of the two optical frequency combs need to be locked, and the bias frequency locking system is particularly complicated

This scheme uses non-coherent measurement technology, but the measurement principle inherits J.Ye's scheme, so it can only measure some discrete length values

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