Fig. 1. Schematic diagram of edge filtering method

Fig. 2. The wavelength of the sound wave is 2 cm

Fig. 3. The wavelength of the sound wave is 20 cm

Fig. 4. The pressure effect of the transverse sound

Fig. 5. The pressure effect of the longitudinal sound

Fig. 6. Reflection spectra of three grating structures and their linear regions ①②③

Fig. 7. Laser reflectivity curves under different grating structures