Recent Trends in Laser Material Research

Abstract

In a brief historical introduction, the invention of the laser is presented as the culmination of prolonged, decades-long efforts in science and technology aimed at the generation and control of electromagnetic radiation of shorter and shorter wavelengths. The close genetic link of the laser with quantum optics, electronics, and electrical engineering is emphasized. The present status of laser R & D is reviewed within a descriptive framework that stresses the commonality in the function ot electronic and laser devices, and that places special emphasis on laser oscillators and amplifiers. Within the confines of the latter, the presentation focuses on the current status of R&D of solid-state laser materials, wherein the consistently successful development of semiconductor lasers is contrasted with alternating fortunes in the R&D of insulator-based solid-state materials.

Three factors are identified as the driving forces behind the renewed interest in insulator-based solid-state laser materials: the present technological requirements for tunable laser sources, either laser-pumped or flashlamp-pumped; the doubling in lasing efficiency in Nd-activated garnets, as resulting from Cr3+ cross-pumping; and Lawrence Livermore’s reassessment of solid-state laser materials for medium- to high-power applications.

As for the future trends in laser R&D, the revolutionary impact of the original discovery is far from being spent, as witnessed by the recent dramatic production of extremely short laser pulses in the femtosecond regime. In science and technology, laser radiation represents nowadays: a probe/tool of unsurpassed finesse in both the temporal and energetic domains; a means for the very precise delivery of energy, on both the short and long distances; a vehicle for ultrafast information transfer; and the key element in the very fast production, processing, storing and retrieval of data. Vigorous future growth is expected in those R&D areas that will skillfully take advantage of the unique properties of laser radiation in order to satisfy technological and societal needs.