A brief discourse upon laser technology.

Therapeutic medicine has become one of the most important applications of laser technology. In 1987 sales of medical lasers reached Dollar 80 million that is more than 15% of the laser market worldwide. Lasers are used in various surgical procedures, ranging from neurosurgery to podiatry. In this discourse we summarize the features of laser radiation that make the laser such a unique light source. The basic elements of a laser, namely the active medium, the energy pump, and the optical resonator are presented and their influence on the emitte radiation is discussed. Finally we describe four types of lasers extensively used in medical applications, the CO2-, the Ar+-, the Nd:YAG-, and the Dye-laser. (IPT)