Fig. 1. Schematic diagram of LiDAR

Fig. 2. Schematic diagram of telephoto optical system

Fig. 3. Relationship between distance d and telephoto ratio k

Fig. 4. Passive optical athermalization system^[17]

Fig. 5. Athermal T'-C' chart in near infrared wavelength band

Fig. 6. Passive optical and mechanical athermalization system

Fig. 7. Through focus changes of three designs at different temperatures

Fig. 8. Changes of three designs with holder materials at different temperatures. (a) Through focus; (b) field curvature; (c) distortion

Fig. 9. Comparison of imaging MTF of lens 1, 2, and 3 at different temperatures. (a), (d), (g) 20 ℃; (b), (e), (h) -40 ℃; (c), (f), (i) 100 ℃

Fig. 10. Comparison of through focus MTF of lens 1, 2, and 3 at different temperatures. (a), (d), (g) 20 ℃; (b), (e), (h) -40 ℃; (c), (f), (i) 100 ℃

Fig. 11. Comparison of RMS radius of diffuse spot of lens with different fields at different temperatures. (a) Lens 1; (b) lens 2; (c) lens 3

Fig. 12. Schematic diagram of lens data in test 1. (a) Through focus changes of lens; (b) temperature-time curve of lens

Fig. 13. Schematic diagram of lens data in test 2. (a) Through focus changes of lens; (b), (c) thermal imaging on two sides of lens at 70 ℃; (d) thermal imaging on one side of lens at 100 ℃; (e) thermal imaging of upper side of lens at 100 ℃; (f) cross target; (g)-(k) imaging of cross at 20, 40, 60, 80, and 100 ℃, respectively

Fig. 14. Imaging effect of telephoto lens combined with LiDAR. (a) Target car; (b) imaging at 20 ℃; (c) imaging at 60 ℃; (d) imaging at 100 ℃