Acousto optics refers to the interaction between sound waves and light waves in solid materials. When an acoustic wave propagates through certain materials, it generates a periodic variation in the material's density and refractive index due to the photoelastic effect.. The deflection and modulation of light by sound enables numerous applications in remote sensing, signal processing, ... https://articlescad.com/acousto-optics-devices-utilizing-sound-waves-to-manipulate-light-31689.html