Synthetic corundum is an essential part of many lasers. In fact, the first working laser was a “ruby laser,” made by Theodore Maiman at Hughes Research Labs in 1960. It employed a synthetic ruby crystal as the “gain medium.” The gain medium is a material in the laser that is the target of an intense burst of light.

That light causes electrons in the gain medium to jump up to a higher energy level causing the emission of photons, which strike other atoms in the gain medium, causing them to be excited and emit more photons. This brief chain reaction produces the very intense light of a laser beam. Lasers are named after the material used as a gain medium, such as “ruby laser” or “titanium sapphire laser” or “YAG laser” (yttrium aluminum garnet).

In just a few decades, lasers have become common items of our society. Tiny lasers are used in CD and DVD players. Lasers are used to cut metal, stone, and other tough materials. Lasers are used to remove tattoos, perform cosmetic surgery, cataract surgery, and LASIK surgery for vision correction.