The ruby laser was the first working laser developed by Theodore Maiman in 1960. It uses a ruby crystal doped with chromium ions as the lasing medium. The ruby laser consists of a polished ruby rod placed between a fully reflective mirror on one side and a partially reflective mirror on the other, forming an optical cavity. When pumped with flashes of light from a xenon lamp, stimulated emission occurs within the ruby crystal, producing pulses of red light with a wavelength of 694nm. Some key applications of the ruby laser include tattoo removal, hair removal, and dermatology procedures.