Spectroscopic, dielectric properties and local structure observation by EXAFS for Nd,Y:CaF₂crystal

Trivalent impurity ions are clustered easily in fluoride crystals. With the addition of Y 3+ spectral properties are greatly enhanced. Low temperature absorption and emission spectra are performed to unfold the optical centers in Nd 3+ ,Y 3+ :CaF 2 crystals. The strongest absorption line at around 790 nm belongs to M luminescence quenched centers in 1%Nd 3+ :CaF 2 ; and at 797 nm to L ' centers for a codoped one. For emission spectra 1049.3 nm and 1068.7 nm are attributed to M ' and N ' non quenched centers; 1054.6 nm to an L ' site in a 1%Nd 3+ ,5%Y 3+ :CaF 2 sample. EXAFS spectra, an intuitive approach, are applied to reveal that the first coordination number of Nd 3+ increased from 9.2 to 10.7 with the addition of Y 3+ ions, and the local lattice expanded.