I’ve always found lasers fascinating, not only as devices but also philosophically. What I mean is this: Natural laser light does not exist in the universe, yet the principle that makes lasers work, called “stimulated emission,” is a fundamental physical property of the universe. Stimulated emission was first predicted by Albert Einstein in 1917, and the first working laser was built in 1960. Actually, the first device built based on stimulated emission was the “maser” first built in the mid-1950s, but it was based on microwaves and not visible light.
The physics and technology to understand and make lasers gets quite complicated. However, all you need to understand from a philosophical perspective is that no laser light existed in the universe before 1960, yet it had always been possible. Humans revealed an obscure physical law of nature and manipulated their environment to make use of it and wow, how useful it has proven to be in science, medicine, consumer electronics, communication. Almost everyone in this country makes use of lasers many times per day without realizing it.
Laser light makes all these things possible. Nature gave the possibility of generating this light, but not the light itself. It took humans to bring that kind of light into existance.
Up next: Laser experiments!