
150 Lasers
Another method for the categorization of lasers is based on the gain medium.
Table5.1 lists some of the best known lasers along with some important informa-
tion about them.
Table5.2 illustrates that the efciency of lasers is usually too low with the excep-
tion of carbon dioxide lasers, which are used in the industry for material processing.
5.4 Excimer Lasers
For most lasers, light is generated by means already described, such as the ow
of electricity in semiconductors and electric discharges in a gas. Another type
of laser is called the excimer laser, which is based on chemi-luminescence. In
excimer lasers, a chemical reacti