Memory from a Cesium Vapor
A beam of light enters a glass cell filled with cesium vapor and changes the internal state of the atoms: this is how information is recorded. A moment later, another beam reads it out by how the atoms absorb light. It's not a hard drive, but rather a notebook that turns its own pages.
Eight such "pages" are created by an acousto-optic deflector — a device that bends light with sound.