Used as a dopant in solid-state devices for optical applications, particularly in phosphors for fluorescent lamps and tricolor lamps. Employed in the production of specialty glasses and crystals that exhibit high refractive index and low dispersion, useful in lenses and laser materials. Serves as a component in scintillation detectors for radiation measurement due to its ability to emit light when exposed to ionizing radiation. Also utilized in research for developing terbium-based luminescent compounds in display technologies and bioimaging.