Fig. 1. Experimental setup for measuring response characteristics of sound signals

Fig. 2. Polarization spectra (blue solid line) and corresponding saturated absorption spectrum (black dash line) of 87Rb 5S1/2Fg=2 to 5P3/2Fe=1, 2, 3 transitions

Fig. 3. Laser frequency fluctuation in time domain of open loop free-running and closed loop frequency stabilization. (a) Under open loop free-running; (b) after loop frequency closing

Fig. 4. Amplitude-frequency characteristics under open loop and closed loop of laser system. Scatter line shows measured results of square wave modulation and black line shows that of dynamic signal analyzer SR785

Fig. 5. (a) Laser frequency fluctuation with 1200 Hz sound stimulant signal; (b) frequency spectrum for laser frequency fluctuation signal

Fig. 6. Acoustic response characteristics of laser frequency fluctuation to sound stimulant signal

Fig. 7. Sound-insulating effect of different soundproofing cases

Fig. 8. Schematic diagram of laser mechanical structure