Rami Arieli: "The Laser Adventure"

Rami Arieli: "The Laser Adventure" Chapter 6 Gas lasers Page 1.

6.1 Gas Lasers

Most elements can be made to lase when they are in the gas state.

Also many molecules (composed of a few atoms each) have been demonstrated to lase.

In a gas laser, the laser active medium is a gas at a low pressure (A few milli-torr).

The main reasons for using low pressure are:

To enable an electric discharge in a long path, while the electrodes are at both ends of a long tube.
To obtain narrow spectral width not expanded by collisions between atoms.

(A few types of special lasers use gas at high pressure).

The first gas laser was operated by T. H. Maiman in 1961, one year after the first laser (Ruby) was demonstrated.
The first gas laser was a Helium-Neon laser, operating at a wavelength of 1152.27 [nm] (Near Infra-Red).