Cr⁴⁺:YAG (Y₃A₁₅O₁₂) is an ideal material for passive Q-switching of Nd:YAG and other Nd and Yb doped lasers in the wavelength range of 0.8 to 1.2 mm. One of the remarkable features of Cr⁴⁺:YAG is high damage threshold of 500-1000 MW/cm². Passive Q-Switching is preferred for simplicity of manufacturing and operation, low cost and reduced system size and weight.
The preliminary experiments of Cr:YAG showed that the pulse width of passively Q-switched lasers could be as short as 9 ns for diode pumped Nd:YAG lasers and repetition as high as 10kHz for diode pumped Nd:YVO4 lasers. Furthermore, an efficient green output @ 532 nm, and UV output @ 355 nm and 266 nm were generated, after a subsequent intracavity SHG in KTP or LBO, THG and 4HG in LBO and BBO for diode pumped and passive Q-switched Nd:YAG and Nd:YVO4 lasers.