Oxide and Fluoride Laser Crystals

Abstract

Crystals doped with metal ions have long been recognized as useful laser media. In fact, laser action was first demonstrated in 1960 on the basis of a ruby laser rod (or Cr3+-doped A1203) (I). Following the discovery that crystals doped with metal ions provide a viable route by which to develop solid-state laser media, hundreds of additional doped crystals have been shown to lase. Many of the early crystals that were of interest to researchers entailed well-known luminescent materials which, by happenstance, also exhibited laser action. Later, many new materials were developed specifi­ cally to serve as laser crystals. In spite of the proliferation of solid-state gain media, few crystals have proven to be useful under practical cir­ cumstances. In fact, the gap between demonstration exercises of laser action and the engineering of practical systems is often wide and difficult to bridge. In order to develop and test new laser crystals, it is first crucial to identify the appropriate means by which to grow and fabricate the crystals. To further optimize the crystal growth conditions, it is necessary to understand the basic physical properties of the melt and solid. In order to successfully