Abstract: A highly oriented thin film of specific barium fluoride materials deposited at low temperatures are useful as Upconversion waveguides.

Abstract: An amorphous upconversion phosphor comprising barium fluoride a combination of rare-earth fluorides including yttrium and lanthanum and dopants, and a waveguide thereof on a substrate selected to have a refractive index lower than a thin film of the phosphor material or any other substrate with an appropriate buffer layer of lower refractive index that the film wherein infrared radiation and visible light are converted to ultraviolet and visible light. The amorphous upconversion phosphor is deposited at temperatures low enough to permit integration into semiconductor materials.