Fig. 1. The end face of the fiber bundle

Fig. 2. Attenuation of fiber bundle

Fig. 3. The schematic of the imaging experimental setup

Fig. 4. The structure and simulation result of distal objective lens

Fig. 5. The thermal image of soldering iron tip

Fig. 6. The imaging comparison between black body and QCL illumination

Fig. 7. The SNR comparison between black body and QCL illumination under different environmental temperature