Fig. 1. Internal optical path of absorber

Fig. 2. Absorber design and structure

Fig. 3. Relationship between η of materials and λ

Fig. 4. Laser field distribution in each region inside absorber. (a) S1;(b) S2;(c) S3;(d) S4

Fig. 5. Highest temperature distributions inside absorber. （a） Inside cavity； （b） inner surface of insulation plate outside cavity

Fig. 6. Temperature distribution of outer surface (including insulation plate) of absorber

Fig. 7. Optical fields of stray light near fiber end cap. （a） Optical fiber end cap mounting surface S5； （b） backlight of fiber end cap

Fig. 8. Influence of cone tip radius on distribution of laser field in absorber. (a) Variation curve of maximum radiation flux coupled back to end cap; (b) radiation flux variation curve of end cap mounting surface; (c) radiation flux variation curve of circumferential side; (d) radiation flux variation curve of laser cone mounting surface; (e) variation curve of maximum irradiance coupled back to end cap; (f) irradiance variation curve of end cap mounting surface; (g) irradiance variation curve of circumferential side; (h) irradiance variation curve of laser cone mounting surface

Fig. 9. Schematic diagram of test light path

Fig. 10. Connection test diagram of fiber end cap and laser absorber

Fig. 11. Tested values of backlight powers of lasers Ⅰ, Ⅱ and Ⅲ by PD

Fig. 12. Thermal image of absorber surface temperature under single laser irradiation

Fig. 13. Thermal image of absorber surface temperature under three laser irradiations at 135 s of light output