Cr4+:YAG Crystal is an excellent crystal for passively Q-switching diode pumped or lamp-pumped Nd:YAG, Nd:YLF, Nd:YVO4 or other Nd and Yb doped lasers at wavelength from 0.8 to 1.2 µm. Because of its chemically stable, durable, UV resistant, good thermal conductivity and high damage threshold (> 500 MW/cm2) and being easy to be operated, it will replace traditional materials, such as LiF, organic Dye and color centers.