The Co²⁺-doped magnesium aluminate spinel (Co:MgAl₂O₄) crystal is an efficient 
saturable absorber that can be used in 1.5μm eye-safe solid-state lasers and is an effective material for passive Q-switched solid-state lasers operating in the near-infrared region. The high-peak-power pulsed laser generated through its passive Q-switching effect can achieve high-power 1.5μm pulsed laser output. It has characteristics such as 
low harm to human eyes, strong penetration ability, low transmission loss, and strong optoelectronic countermeasure ability. It operates at wavelengths ranging from 1200 to 
1600nm and is especially suitable for the 1540nm Er:glass laser which is eye-safe. It can be widely applied in fields such as free-space optical communication, rapid battlefield 
ranging, and lidar for unmanned equipment.