An acousto-optic device includes an acousto-optic medium having a multi-layer nanostructure; and a sonic wave generator configured to apply sonic waves to the acousto-optic medium having the multi-layer nanostructure. The acousto-optic medium having the multi-layer nanostructure includes a second layer formed of at least two materials that have different dielectric constants and alternate with each other; and a first layer disposed on a first surface of the second layer and formed of a first material, and/or a third layer disposed on a second surface of the second layer and formed of a fourth material.