There are two types of lasers, pulsed and continuous. The pulsed lasers use a kind of chain reaction to construct an extremely intense, sudden pulse of light. The continuous lasers operate at constant power as long as power is supplied to them. One of the most powerful pulsed laser systems in the world is right here at UT, used for basic research on states of matter at very high energy density.

Green laser pointers use Diode Pumped Solid State Frequency Doubling technology. They begin with a high power infrared laser diode that generates light at 808nm, which pumps a crystal of Nd:YVO4 (Neodymium-doped Yttrium OrthoVanadate). That crystal generates light via stimulated emission, at 1064 nm, which feeds a KTP (Potassium Titanyl Phosphate, KTiOPO4) intracavity frequency doubler, which produces a green beam at 532 nm. The green beam then travels thru an output coupler, an expanding lens, an IR filter to remove unwanted IR from the beam, then thru a collimating lens and finally exits thru a glass output window. The IR filter is needed to elminate the intense infrared light that gets through the system, which is dangerous since it is invisible to the eye. The green beam itself is also very, very dangerous to the eye.