New materials enabling new laser systems

Summary form only given. Selecting from but a handful of commercially available laser crystals, laser designers have produced an impressive array of solid state lasers able to perform a wide range of scientific, industrial and military applications. Laser design possibilities were enormously expanded with the development in the late 1980's of efficient bright, and powerful semiconductor laser diodes as pump sources for solid state lasers. Despite this, it sometimes proves difficult, if not impossible, to design lasers meeting some applications requirements, when drawing only on presently commercially-available laser crystals, especially when particularly demanding size, weight, and efficiency requirements are imposed. Thus, there continues to be a need to identify, characterize, and develop novel laser crystals possessing characteristics that significantly broaden design options for future laser devices and systems. Because the cost is rather large to transition a newly discovered optical material from laboratory experiments to commercial readiness, it is necessary that such materials possess significantly distinct and enabling characteristics, relative to available materials, and that the intended application(s) be sufficiently highly valued. Fortunately, since the discovery of the laser /spl sim/40 years ago, an extensive array of modeling tools, device design experiences, and material property data bases have evolved, which can be exploited to guide the search for applications enabling new laser materials. By way of example, the author considers in detail the search leading to the discovery of the new class of room-temperature, diode-pumped, tunable mid-IR lasers based on tetrahedrally-coordinated, divalent 3d-transition metal ions in II-VI chalcogenide crystals.