Used in research and specialized industrial applications where high purity rare earth materials are required. Commonly utilized in the production of solid-state lasers, particularly in yttrium-iron-garnet (YIG) and yttrium-lithium-fluoride (YLF) lasers doped with holmium, enabling efficient mid-infrared emission for medical and military uses. Also employed in nuclear control rods due to its high thermal neutron absorption cross-section. Serves as a calibration standard in spectroscopy and magnetic studies because of its distinct magnetic properties. The foil form allows for precise integration into layered materials, sensors, and electronic components.