Abstract: A radiation wavelength conversion device is implemented in the form of a waveguide that includes a single crystal halide-based cladding layer, and a halide-based active layer. The active layer has a greater refractive index than the cladding layer, is approximately lattice matched with the cladding layer, and includes a dopant that causes it to respond to input radiation at one wavelength by emitting radiation at a different wavelength. The active layer can either form part of a laser resonator cavity, or can operate through spontaneous emission. It is preferably about 3.5-5 microns thick to induce single-mode propagation, and can be divided into separate waveguiding channels to limit beam fanning. The device is operable at room temperature, and can be fabricated using conventional microelectronics techniques.

Abstract: A radiation wavelength conversion device is implemented in the form of a waveguide that includes a single crystal halide-based cladding layer, and a halide-based active layer. The active layer has a greater refractive index than the cladding layer, is approximately lattice matched with the cladding layer, and includes a dopant that causes it to respond to input radiation at one wavelength by emitting radiation at a different wavelength. The active layer can either form part of a laser resonator cavity, or can operate through spontaneous emission. It is preferably about 3.5-5 microns thick to induce single-mode propagation, and can be divided into separate waveguiding channels to limit beam fanning. The device is operable at room temperature, and can be fabricated using conventional microelectronics techniques.

Abstract: An upconversion system and method for producing red, green and/or blue emissions in response to an infrared pump is operable at room temperatures. Implemented either as a laser or as phosphors, the host medium has a hexagonal CsNiCl.sub.3 -type crystal structure, a phonon wave number less than 200 cm.sup.31 1, and a rare earth dopant occupying paired lattice vacancies. The host medium has the formulation AMX.sub.3, where A is a monovalent metal, M is a divalent metal and X is a halogen; the system has been demonstrated with CsCdBr.sub.3 :Er. Green, blue and red emissions are stimulated with infrared pumps of about 800 nm, 980 nm and simultaneous 800/980 nm, respectively.

Abstract: A full color upconversion laser pumped by a single wavelength infrared laser source is disclosed. The pump energy excites a rare earth doped crystal and can simultaneously lead to laser emission at several wavelengths. The laser includes a crystal of YLiF.sub.4 :Er 5% fabricated in a monolithic structure which incorporates the laser mirrors as dielectric coatings on spherical surfaces of the crysal rod; the mirrors are optically reflecting at one or more of the desired output wavelengths. The laser rod is mounted in a helium cryostat that permits the operating temperature to be varied between 15.degree. and 120.degree. K. The pump energy is supplied through one of the mirrors specifically designed to be simultaneously highly reflecting at the laser wavelength and highly transmitting at the pump wavelength. To achieve optimum efficiency a lens is used in the pump path to focus the pump beam in such a manner as to provide a match of the laser mode size and pumped region of the crystal.