5.1 INTRODUCTION

A solid-state laser is a device in which the active medium is based on a solid material. This material can either be an insulator or a semiconductor; semiconductor lasers are covered in Chap. 7, and will be discussed again here, but as pump sources for solid-state lasers. Solid-state lasers based on insulators include materials which are lightly doped with or, in some cases, are stoichiometric in, the lasing ions, and materials which contain a crystalline defect as the lasing species, known as F-center lasers.

Even though the physics and engineering of solid-state lasers are both mature fields, they are burgeoning with new activity. Whilst many concepts and laser designs and applications have been established and form the basis fora B$/year level industry, each year continues to bring remarkable new discoveries that open new avenues of research, or provide the basis for new engineering configurations. This chapter is intended to provide a brief, and mainly tutorial, account of the physics basis of solid-state lasers, and also convey a sense of the breadth of the field.

The principle of laser action was first experimentally demonstrated in 1960 by T. Maiman.1 This first system was a solid-state laser. A ruby crystal served as the active element, and it was pumped with a flashlamp. With his report, the main principles of laser action were established (see Fig. 5.1). The idea of optically pumping a laser rod was realized, as was the use of an impurity...