Passive Q-switches or saturable absorbers generate high power laser pulses without the use of electro-optic Q-switches, thereby reducing the package size and eliminating a high voltage power supply. Co2+:MgAl2O4 is a relatively new material for passive Q-switching in lasers emitting from 1.2 to 1.6μm, in particular, for eye-safe 1.54μm Er:glass laser, but also works at 1.44μm and 1.34μm laser wavelengths. Spinel is a hard, stable crystal that polishes well.
E-O Q Switch alters the polarization state of light passing through it when an applied voltage induces birefringence changes in an electro-optic crystal such as KD*P. When used in conjunction with polarizers, these cells can function as optical switches, or laser Q-switches.
Cr4+:YAG 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 1.2um.It is superior stability and reliability, long service life and high damage threshold.