Instead of using a liquid or gas as in dye or gas lasers, a solid-state laser uses a solid as its gain medium.

Instead of using a liquid or gas as in dye or gas lasers, a solid-state laser uses a solid as its gain medium. Semiconductor lasers are also solid-state devices, however they are typically classified separately from traditional laser diodes.

Metal cutting, medical procedures including eye surgery, laser printer and projector RGB light sources, environmental instrumentation measures, optical transmission systems, and even nuclear fusion are just some of the many uses for solid-state lasers.

The divergence of solid-state lasers varies widely, from 1 milliradian to 20 milliradians, which is a major drawback of these devices. Similarly to CO2 lasers, the output power is relatively low. Loss of power happens when the rod gets too hot, as is the case with solid-state lasers due to thermal lasing.