Laser crystals are optical crystals that are doped with laser-active ions and used as gain media for solid-state lasers. They can convert the energy supplied from the outside into highly parallel and monochromatic laser beams with spatial and temporal coherence. Laser crystals have different characteristics and properties depending on the type of dopant and host crystal. Some of the most common types of laser crystals are Nd:YAG, Yb:YAG, Ti:sapphire, Er:YAG, Nd:YLF, Nd:YVO4, etc. These laser crystals have different absorption and emission wavelengths, typical power ranges, and applications. The following table summarizes some of these parameters for some common laser crystals.