All - Solid - State Four - Color Laser

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The goal of this project is to develop a solid state laser that produces visible output wavelengths, including the commercially compelling blue wavelength. The basic architecture of the device consists of a single-mode optical fiber doped with Pr3+ and YW+ ions. When the ions are simultaneously pumped with a near infrared laser (860 rim), complex energy transfer processes involving multiple excited ions leads to population of a high-lying energy level of Pr3+. Results include the demonstration of the existence of a photon avalanche mechanism responsible for creation of the population inversion and demonstration of the highest optical-to-optical efficiency of any up-conversion laser reported to date. A US Patent was awarded for this invention in 1998. Background and Research Objectives Everyone knows what a megabtye is and complains about not having enough of them. Consumer demand for digital mass-storage devices thus currently makes for a $50 billion per year industry; by all accounts, this demand will soar when the information-based economies of the next century begin to emerge. Optical memory materials offer the greatest technological leverage we know of for rapidly increasing the number of megabytes storable on one square inch of mass-storage recording medium. In turn, the best strategy for increasing the density of information recordable on optical materials is to shorten the operating wavelength of the storage device’s laser read-write heads. Areal optical storage density scales as the inverse square of the operating wavelength, hence blue-or uv-based optical disk drives promise a fourto six-fold expansion in memory capacity over the infrared optical chives available today. Fifty gigabytes of data could fit onto a single’ twoinch disk written at 450 nrn, even terabyte storage capacities will become practical pending the development of multilayer/multiwavelength optical recording materials. *Principal Investigator, e-mail: [email protected]