What device did Bell invent to transmit sound via a beam of light?

Answer

The photophone

The photophone functioned essentially as an optical telephone. By utilizing a beam of light to carry sound, it allowed Bell to explore communication methods that moved beyond the constraints of physical wires, reflecting his continuous fascination with the physics of sound transmission.

What device did Bell invent to transmit sound via a beam of light?
inventionAlexander Graham BellinventorMotivation