Nd: YAG Optical Crystal Lens (Neodymium Doped Yttrium Aluminum Garnet) has been and continues to be the most widely used laser crystal for solid-state crystal material. Its laser parameters are a good compromise between the strengths and weaknesses of its competition. Nd: YAG crystals are used in all types of solid-state laser systems-frequency-doubled continuous wave, high-energy Q-switched, and so forth. Compared with other laser crystals, its fluorescence lifetime is twice more than Nd: YVO4, and thermal conductivity is also better.