High-energy laser beam parameter diagnosis method based on fiber Bragg grating and diagnosis instrument

Abstract

The invention discloses a high-energy laser beam parameter diagnosis method based on a fiber Bragg grating and a diagnosis instrument. According to the principle that the central wavelength of the fiber Bragg grating linearly drifts along with temperature, large-area and high-power-density laser spots are measured in real time for a long time by the aid of the characteristics of small absorption coefficient of fibers for high-energy laser, small absorption area and high surface-area-to-volume ratio and by means of fiber Bragg grating wavelength demodulation. In addition, a fiber Bragg grating array can be flexibly changed according to practical measuring requirements, for example, the size of the array, the length of a used fiber Bragg grating grid region, the radius of each fiber and the like can be changed, and different laser spots, different resolution ratios and different sensitivities can be measured. Besides, the diagnosis instrument can be used for measuring laser beam parameters such as high-power laser energy distribution, overall energy and the like, and has the advantages of simple structure, high resistance to laser damage and the like.

Description

technical field [0001] The invention relates to a method and device for measuring laser energy parameters, in particular to a method and device for diagnosing parameters of high-energy laser beams based on the principle of optical fiber optical temperature measurement. Background technique [0002] High-energy lasers refer to lasers with an average power greater than 10,000 watts, a duration of more than several seconds, and an output energy of more than tens of thousands of joules. They have important industrial and military application prospects. The energy and energy density distribution of high-energy lasers are important parameters to characterize the effectiveness of lasers. Usually, the array element heat absorption method is used to measure the output energy parameters of high-energy lasers absolutely. After the incident energy is absorbed by the absorber unit, the light energy is converted into thermal energy, and the energy of the high-energy laser incident on the ...

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Problems solved by technology

[0003] In the actual measurement of the measurement system, the heat absorption unit has the disadvantage of being easily ablated by the laser in the application, and because the heat balance time is long, it brings inconvenience to the measurement. The existing methods of cooling by water circulation or air convection are only Can be improved to a certain extent, with the increase of high-energy laser output power, the use of this measurement method will inevitably be limited

In addition, the measurement device based on the principle of heat absorption absorbs or blocks all the laser energy during use, which cannot meet the needs of online monitoring of the laser beam in the experiment.

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