Judd‐Ofelt Analysis of the $Er3+$ Ions in Double‐Doped $CaF2:(Er3+,Yb3+)$ Crystal Available to Purchase

The double‐doped $CaF2:(0.14 mol% ErF3,1.31 mol% YbF3)$ and $CaF2:0.12 mol%$ $ErF3$ crystals were grown in our crystal research laboratory using the vertical Bridgman method. The Judd‐Ofelt intensity parameters $Ω2,$ $Ω4,$ and $Ω6$ for $f−f$ transitions of $Er3+$ ions were determined from the optical absorption spectra using various groups of transitions. Using the J‐O parameters the radiative transition probability, oscillator strength, branching ratio and radiative lifetime of $Er3+$ transitions have been calculated. The radiative transition probability and radiative lifetimes are compared to those of $Er3+$ transitions in other hosts.