KGW (Potassium Gadolinium Tungstate) is a crystal that is commonly used as a laser gain medium, particularly in solid-state laser systems. This crystal has a high thermal conductivity and a high absorption coefficient, which make it well suited for high-power laser applications. The crystal is typically doped with neodymium ions to increase the laser gain and produce a laser light with a specific wavelength. In addition to its use as a laser gain medium, KGW has also been investigated for use in medical imaging and other optical applications.