Solid state laser
A solid state laser is one in which the excited medium is a solid, either a glass or a crystal doped with an ion, which will determine the produced wavelength. Many variants exist or have existed. Ruby doped with chromium (Cr4+) was the material for the first laser which worked using pulses (Theodore Maiman, 1960). Garnet is used in YAG lasers (Yttrium Aluminium Garnet). Various rare earths have been used.
Solid lasers can emit from infrared to ultraviolet and supply high power, running in continuous or pulse mode.