Used as a dopant in stainless steel to improve grain refinement and mechanical strength. Employed in the production of special optical glasses and ceramics due to its ability to modify refractive index and enhance durability. Serves as an effective component in solid-state lasers, particularly in combination with other rare-earth elements, for high-power and precision applications. Utilized in radiation-detecting devices because of its high sensitivity to X-rays and gamma rays. Also applied in research for developing advanced catalysts and in the fabrication of thin-film coatings for optical components.