The Photophone and Early Theories of Light

The first important attempt to get light to perform a task that lasers perform today came in the year 1880.

Noted American inventor Alexander Graham Bell performed an experiment that showed how light might be used to carry a person's voice from one location to another. To accomplish this, Bell used a device he called a photophone, which consisted of a thin mirror, a receiver that could detect light, some wires, and an earpiece. Bell placed the mirror so that sunlight reflected off of its surface and traveled more than one hundred feet to the receiver. When a person spoke near the delicate mirror, it vibrated slightly. This caused the sunlight being reflected into the receiver to vibrate, too. The receiver then changed the light vibrations into an electrical signal, which traveled through the wires to...