Seawater temperature measuring system and method based on low-pulse-energy high-repetition-frequency laser

Abstract

A seawater temperature measuring system based on a low-pulse-energy high-repetition-frequency laser comprises a laser device, a reception system, a signal collection system and a signal processing andparameter inversion unit; the laser device generates 532nm low-pulse-energy high-repetition-frequency laser and focus detection light to a water area of a specific depth; the reception system receives backward Rayleigh Brillouin diffusion light from the water area of the specific depth; the signal collection system uses the backward Rayleigh Brillouin diffusion light to form an interference ringvia an F-P etalon, and generates a 2D interferogram on an ICCD finally via focusing by a rear-end focusing lens; and the signal processing and parameter inversion unit extracts high-precision Brillouin frequency shift from the 2D interferogram, and obtains the seawater tempearuter of the water area of the specific depth via calculation according to a seawater temperature inversion model.

Description

technical field [0001] The invention relates to the technical field of ocean temperature remote sensing, in particular to a seawater temperature measurement system and method based on a low pulse energy high repetition frequency laser. Background technique [0002] Brillouin scattering is an inelastic scattering of light due to density fluctuations of a medium. This medium density fluctuation will also cause a change in the frequency of the photon, which is reflected in the frequency spectrum relative to the frequency shift of the incident photon. When a large number of photons of the same frequency enter the medium in the same direction (such as laser), the scattered light will not only shift in frequency, but also cause a broadening effect due to the interaction with the atoms or molecules of the medium, and finally it is reflected in the spectrum as relative to the laser A Brillouin scattering peak with a shifted center frequency. The offset (Brillouin frequency shift) ...

AI Technical Summary

Problems solved by technology

(2) The radar receiving system must be able to accurately measure the back Brillouin scatter frequency shift

(3) The whole system must have strong anti-vibration and anti-interference ability

[0006] In previous systems, Nd:YAG pulsed lasers (500mJ, 10Hz repetition rate) were often used to measure the temperature profile of deep underwater distances, but such high-pulse energy lasers are large in size, heavy in weight, and It is sensitive to vibration, which affects its large-scale application in practice to a certain extent.

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