Solid laser source applicable to generation of polychromatic sodium guide star

Abstract

The present invention relates to a solid laser source applicable to the generation of a polychromatic sodium guide star. The device comprises a semiconductor pump light source, a laser oscillator, a second harmonic generation module and a fourth harmonic generation module; the semiconductor pump light source is used for emitting pump light; the pump light is pulsed light; the repetition frequency of the pulsed light ranges from 200 Hz to 1 KHz; the pulse width of the pulsed light ranges from 80 microseconds to 300 microseconds; the laser oscillator is used for oscillating the pump light emitted from the semiconductor pump light source to generate laser of a first wavelength; the second harmonic generation module is used for converting the laser of the first wavelength into laser of a second wavelength, wherein the second wavelength is smaller than the first wavelength and is larger than 330 nm; and the fourth harmonic generation module is used for converting the laser of the second wavelength into 330-nm laser. Since the front part of a single output pulse has high peak power, a nonlinear attenuation effect appears in atmospheric transmission, and as a result, attenuation of the 330-nm laser caused by atmosphere is weakened; and the rear part of the single output pulse has proper average power which is matched with sodium atom density in the sodium layer of the atmosphere, and a large number of photon echoes can be generated.

Description

technical field [0001] The invention relates to the technical field of lasers, in particular to a solid-state laser source suitable for producing polychromatic sodium guide stars. Background technique [0002] When large ground-based telescopes observe space objects such as celestial bodies, disturbances such as atmospheric turbulence will greatly reduce the imaging resolution. Adaptive optics can be used to correct for these perturbations, allowing the telescope to achieve near-diffraction-limited resolution. Adaptive optics correction requires a guide star (called a beacon), and the wavefront of the light signal emitted by it is used as a standard, and the error signal is obtained by measuring the phase distortion of the wavefront through the atmosphere, so as to realize the imaging of the observation target Correction. The 589nm laser is currently the most commonly used monochromatic sodium beacon laser source in the world. Compared with monochromatic beacon guide star...

AI Technical Summary

Problems solved by technology

Some people also listed the advantages and disadvantages of the two schemes. Among them, the disadvantages of two-photon excitation: two high-power and narrow-linewidth laser sources of 569&589nm are required, the technology is difficult, and the system structure is complex; the advantages of single-photon excitation: laser source The technical complexity is relatively small, the laser system is simple, and the echo photon number efficiency is high

However, when the laser energy is high to a certain extent, the strong laser will cause changes in the characteristics of the atmosphere, so that the attenuation of the laser by the atmosphere presents nonlinear characteristics

Images