Fig. 1. Optical design model of beam expander

Fig. 2. Design model of beam expander structure

Fig. 3. Integrated analysis process of laser beam expander

Fig. 4. Deformation cloud map of beam expander under 40 ℃ thermal load. (a) Overall deformation of the beam expander structure;

Fig. 5. Changes of system wavefront RMS at 0 ℃ to 40 ℃

Fig. 6. Changes of the low-order Zernike coefficient of the system at 0 ℃ to 40 ℃

Fig. 7. Ambient temperature test platform. (a) Schematic diagram of testing optical path; (b) photos of the test site

Fig. 8. Ambient temperature test wavefront. (a) 0 ℃ test wavefront; (b) 20 ℃ test wavefront; (c) 40 ℃ test wavefront

Fig. 9. Comparison of simulation and test results. (a) Power variation of beam expander; (b) wavefront RMS variation of beam expander

Fig. 10. Compensation effect of different adhesive layer thicknesses on system wavefront and power. (a) Thermal compensation effect at 0 ℃ (spot diameter 10 mm); (b) thermal compensation effect at 40 ℃ (spot diameter 10 mm); (c) thermal compensation effect at 40 ℃ (layer thickness 0.25 mm)

Fig. 11. Simulation results of system wavefront after thermal compensation at different temperatures. (a) -10 ℃; (b) 0 ℃; (c) 10 ℃;

Fig. 12. Wavefront test results at different ambient temperatures. (a) 0 ℃; (b) 20 ℃; (c) 40 ℃