Design of ten-thousand-watt laser beam expander and research on the thermal effect

Figure 1 Schematic diagram of high-power laser reflection off-axis beam expansion system Figure 2 System Image Quality Evaluation Diagram Figure 3 Three dimensional model of a 10000 watt beam expander device Figure 4 Working coordinate system of the primary and secondary mirrors of the beam expander device Figure 5 Thermal power spectrum loading of Gaussian distribution on the surfaces of primary and secondary mirrors Figure 6 shows the temperature distribution of the primary and secondary mirrors after 150 seconds of light emission (initial temperature: 22 ° C) with η 1=η 2=100ppm; (a) Sapphire secondary mirror; (b) Glass ceramics secondary mirror; (c) Main mirror Figure 7 shows the highest temperature rise curve for different film absorption coefficients during the light emission process; (a) Main mirror; (b) Secondary mirror Figure 8 shows a mirror distortion at 150s when η 1=η 2=200ppm. (a) Sapphire secondary mirror; (b) Glass ceramics secondary mirror; Figure 9 shows the degradation curve of the mirror type and beam quality of the beam expander with respect to the emission time, where η 1=η 2=200ppm. (a) RMS values of primary and secondary mirror surfaces; (b) Beam quality degradation rate β value Figure 10: The variation curve of the output optical axis of the beam expander with the time of light emission, where η 1=η 2=200ppmFigure 11 shows that η 1=η 2=200ppm, Δy=3mm，t=150s， Temperature distribution of the device Figure 12 shows that η 1=η 2=200ppm, Δy=3mm， t=150s， Mirror distortion; (a) Main mirror; (b) Secondary Mirror (Sapphire) Figure 13 shows the degradation of the surface shape and beam quality of the beam expander caused by the displacement of the near-field spot of the incident laser at 150s; (a) Primary and secondary mirror surface types; (b) Beam quality degradation rate β curve Figure 14 shows the variation of the output optical axis of the beam expander at 150 seconds of light emission. (b) Optical axis pointing change curve Figure 15 Physical picture of laser beam expander device Figure 16 Schematic diagram of laser power, beam quality, and optical axis pointing test Figure 17 shows the distortion of the spot shape and the distribution of light intensity during the light emission process. (a) 1 second; (b) 15 seconds; (c) 35 seconds; (d) 65 seconds; (e) 95 seconds; (f) 140 seconds Figure 18 Thermal image of the beam expander at 140s of light emission Figure 19 Laser power test curve Figure 20 shows the test curve of laser beam quality degradation rate β during the light emission process. (a) Laser light source; (b) Laser after beam expansion Figure 21 shows the variation curve of optical axis drift during the light emission process. (a) Laser light source; (b) Laser after beam expansion