Red, green, blue upconversion laser pumped by single wavelength infrared laser source

摘要

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° and 120° 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.