Gas lasers Excimer lasers use reactive gases such as chlorine and fluorine mixed with inert gases such as argon, krypton, or xenon. Microscopy Laser microscopes and setups for optical coherence tomography OCT provide images of, e. Dye lasers Semiconductor lasers diode lasers are not solid-state lasers.
Additional laser microscopy techniques include harmonic microscopy, four-wave mixing microscopy  and interferometric microscopy. Fiber-optic sensorsoften probed with laser light, allow for the distributed measurement of temperature, stress, and other quantities e.
A mirror at one end of the laser tube keeps the photons bouncing back and forth inside the crystal over and over again. Such pulses can be used to initiate and analyze chemical reactions, a technique known as photochemistry.
Lasers are used for eye lens curvature corrections. Designated the YAL-1it was intended to kill short- and intermediate-range ballistic missiles in their boost phase. The photons that atoms give off zoom up and down inside the ruby crystal, traveling at the speed of light. An optical communication system consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal.
Alignment lasers may simply emit a Gaussian laser beam, forming a circular spot on a workpiece, a line, a cross, or some other pattern. Semiconductor lasers can also be used for this purpose.