Artificial Beacons are man-made guide stars that are created in the atmosphere using specific lasers emitting on the ground. In the field of astronomical target detection and imaging, in order to improve the imaging resolution of large telescopes, artificial beacons are required to detect and adaptively correct the wavefront distortion caused by atmospheric turbulence. Artificial beacons usually contain two types: sodium beacons and Rayleigh beacons. As sodium beacon is highly located in the atmosphere 90km ~ 100km, much higher than the earlier application of Rayleigh beacon (height 10km ~ 20km), adaptive optical system to provide full atmospheric distortion information, it is the most ideal artificial beacon. High-performance sodium beacon lasers are the prime prerequisite for producing high-brightness sodium beacons. According to the principle of resonant absorption backscatter to generate sodium beacon and the large variation of density of sodium atom column, the sodium beacon laser must have the characteristics of precise spectrum control, high average power and high beam quality. Due to the fact that only the dye in the various laser media can directly generate sodium beacon laser, the dye laser has the inherent defects of strong pollution, bulky and poor reliability. Therefore, since the first report of the sodium beacon laser in 1987, And the development of sodium beacon laser, which meets the technical requirements and practical requirements of engineering at the same time, has been a difficult and hot topic for scientists to research. Based on the physical mechanism of the sodium beacon production and the overall system technology, the project scientifically selected the pulse system sodium beacon laser which is very different from the mainstream sodium beacon laser in China and abroad, and chose the two systems based on the 1064nm and 1319nm two The average power of the LBO crystal is 81W, the single pulse energy is 325mJ, the beam quality is M2 <1.3, the center wavelength is 589.1591nm, Linewidth less than 1GHz, pulse width of about 150μs sodium beacon laser output. This is the highest average power all-solid sodium beacon laser in the world. At the same time, a novel spectral line control method of "0 + 2 = 2" mode is proposed (that is, a single longitudinal mode laser and a multi-longitudinal mode laser are used to separate the center wavelength and the line width of the sodium beacon laser) Based on electro-optic phase modulation and high-speed PZT driving technology, a new type of sodium beacon laser line structure with line width tuning and frequency chirping is achieved for the first time in the world. (1) The design idea of ​​asymmetric injection and frequency generation of sodium beacon laser is proposed. Based on the traditional symmetry injection and frequency theory and the difference of quantum conversion and thermal effect between 1064nm and 1319nm fundamental laser, In the design method of pulse energy, beam quality and time waveform are asymmetric, the comprehensive performance of 1319nm laser is far less than the physical defect of 1064nm laser. The 1064nm laser based on 600mJ, M2 ~ 1.8, smoothing time waveform and 400mJ, M2 ~ 3.0, 1319nm laser with relaxation oscillation (the ratio of the brightness of the two is about 6.4: 1) and the frequency of extracavities, the world's highest average power and near-diffraction limit beam quality solid-state sodium beacon laser has been successfully achieved. (2) A new type of sodium beacon laser line control method with "0 + 2 = 2" mode is proposed and adopted. A single longitudinal mode laser (1064nm) and a multi-longitudinal mode laser Laser center wavelength, line width control measures to separate the former control center wavelength, the latter control line width, the effective solution to the sodium beacon laser center wavelength, line width, the need for high precision control of the technical problems. Based on the electro-optical phase modulation technique, the 1064nm laser linewidth of a single longitudinal mode is broadened, and the modulation broadening of the laser linewidth of the sodium beacon is successfully achieved. That is, in a sub-GHz linewidth multi-longitudinal mode fine structure, each discrete longitudinal mode Achieve 100MHz ~ 500MHz widening. (3) Combining temperature and PZT wavelength tuning technology, high-precision wavelength detection technology and PID feedback control algorithm effectively solve the technical problem that the pulse center sodium beacon laser mode center frequency jumps rapidly and realize Accurate closed-loop and high-speed periodic scanning (also known as frequency chirp) of the pulsed sodium beacon laser center wavelength, long-wavelength wavelength alignment accuracy better than ± 0.15pm (PV value) at 589.1591nm, chirp amplitude of 150MHz, bandwidth of 5 ~ 20kHz. The result is close to the measuring device limit ± 0.06pm. (4) In the 1064nm and 1319nm fundamental frequency lasers, the multi-stage and multi-pass link amplification technology which combines optical fiber amplifier with rod-shaped solid state amplifier is used to integrate the advantages of both fiber and bulk solid-state amplifiers. On the basis of compensation, the compensation technology of multi-stage series rod-like pump module aberration mutual compensation is proposed to realize the fundamental laser output with the total pulse energy greater than 1.5J (the pulse energy for the sum frequency is 1J) and the high beam quality. (5) The low-temperature and high-efficiency sheet-type and frequency-crystal far-field and frequency technology are adopted, which greatly reduces the LBO crystal thermal gradient at high power loading and effectively suppresses the temperature phase mismatch effect of frequency and efficiency, and achieves a 32.5% Frequency conversion, the technical indicators have reached the international advanced level. 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March 30, 2024