Fig. 1. Optical fiber interferometry-based ultrasonic sensors

Fig. 2. MZI optical fiber ultrasonic sensors^［44-46］

Fig. 3. MI optical fiber ultrasonic sensors^{［55，57］}

Fig. 4. SI optical fiber ultrasonic sensors^{［59，61］}

Fig. 5. FPI optical fiber ultrasonic sensors^［75-77］

Fig. 6. Underwater ultrasonic detector based on FBG^［86-87］

Fig. 7. Experimental setup for ultrasonic measurement based on DBR fiber laser^［89］

Fig. 8. Diagram of ultrasonic experimental system for chirped FBG multiplexing measurement^［96］

Fig. 9. Seismic physical model imaging at University of Houston^［106］

Fig. 10. Shale physical model imaging at Beijing Petroleum University^［108］

Fig. 11. Ultrasonic imaging of seismic physical models using a phase-shifted fiber Bragg grating^［110］

Fig. 12. Interferometric optical fiber ultrasonic sensors^{［111-112］}

Fig. 13. FBG optical fiber ultrasonic sensors^{［113-114］}

Fig. 14. Experimental setup of optical fiber ultrasonic testing system

Fig. 15. Photograph of the designed 3D seismic physical model corresponding to the structure in southern Sichuan area^［114］

Fig. 16. Scanning imaging of seismic physical model^［114］

Fig. 17. Schematic of laser ultrasound

Fig. 18. Laser ultrasonic system based on laser interferometer^［31］

Fig. 19. Imaging of seismic physical model based on CONAs^［115］

Fig. 20. Composite particles of SiO₂/C/Fe₃O₄ with photoacoustic effect^［117］