Used in the production of specialty optical fibers and laser materials due to its ability to modify refractive index and enhance performance in infrared transmission. Employed as a dopant in solid-state lasers, particularly in high-power and tunable laser systems. Serves as a component in upconversion phosphors for display technologies and bioimaging. Applied in thin-film coatings for optical devices, providing durability and anti-reflective properties. Also utilized in research for developing new ceramic materials with improved thermal and mechanical stability.