Cr:YAG is a laser active crystal that is doped with chromium ions (Cr+4). It is a type of solid-state laser that is formed by doping yttrium aluminum garnet (YAG) with chromium ions. Cr:YAG is a useful laser crystal because of its high thermal conductivity and good optical quality. It has been used in a variety of laser applications, including pumping sources for other lasers, frequency conversion, and as a gain medium in its own right for laser surgery, scientific research, and material processing. Cr:YAG has a relatively high thermal conductivity, which makes it well suited for use in high-power laser systems, and it has a broad absorption band that allows for efficient pumping with flashlamps or diode lasers. It also has a good thermal stability and a high damage threshold, making it well suited for use in industrial and scientific applications.