Bulk Crystal Growth, First-Principles Calculations, and Mid-Infrared Spectral Properties of Dy3+Doped and Dy3+/Nd3+Codoped LaF3Single Crystals

Dy3+doped and Dy3+/Nd3+codoped LaF3single crystals were successfully grown by the Bridgman-Stockbarger method in a self-made medium frequency furnace. The crystal structures of LaF3were investigated, and their geometry optimizations were carried out. The electronic structures including band structure and density of state were calculated by using first-principles calculations based on density functional theory. The polarized absorption and emission spectra including near-infrared and mid-infrared fluorescence spectra were measured at room temperature. The energy transfer mechanism from Nd3+ion to Dy3+ion was presented, and the microscopic transfer parameters were calculated based on the phonon-assisted energy transfer theory. In summary, two promising routes of Dy3+/LaF3crystal pumped by 1280 nm LD and Dy3+/Nd3+/LaF3crystal pumped by 790 nm LD were proposed for a mid-infrared laser.