Acousto-optic effect

The acousto-optic effect occurs when sound waves (acoustic waves) interact with light within a material. The sound waves create periodic changes in the material’s density and refractive index, forming a moving diffraction grating. When light passes through this region, it can be deflected or split into different directions, depending on the sound waves' properties. This effect is utilized in devices like tunable filters, modulators, and scanners, allowing precise control of light beams by adjusting sound waves, without physically moving parts. Essentially, it's a way to steer or modulate light using sound-induced changes in a medium.