Fig. 1. Experimental setup diagram of generation and collection of laser acoustic signal

Fig. 2. Time-domain and frequency-domain waveforms under different spot diameters. (a) Time-domain waveform; (b) frequency-domain waveform

Fig. 3. Time-domain and frequency-domain waveforms under different laser pulse widths. (a) Time-domain waveform; (b) frequency-domain waveform

Fig. 4. Time-domain waveform and power spectrum of laser-sound at different time. (a) Time-domain waveform; (b) power spectrum

Fig. 5. Power spectrum of laser-sound signal with different laser energies

Fig. 6. Absorptivity in underwater acoustic channel at different frequencies

Fig. 7. Simulation results of laser-sound signal under sound velocity gradient generated by HM2000 0370 ARGO buoy. (a) Sound velocity gradient generated by HM2000 0370 ARGO buoy; (b) three-dimensional propagation loss of laser-sound signal

Fig. 8. Power spectrum of laser-sound signals at different distances

Fig. 9. Pre-compensation energy detector

Fig. 10. Monte-Carlo simulation process of pre- compensation energy detector

Fig. 11. Monte-Carlo simulation result of pre- compensation energy detector

Fig. 12. Time-domain signal and power spectrum in tank test. (a) Time-domain signal; (b) power spectrum