Optical absorption and fluorescence properties of Er3+ in sodium borate glass

Spectroscopic properties of $Er³⁺$ ions in sodium borate glass have been studied. The indirect and direct optical band gaps $(E_opt)$ and energy level parameters (Racah $(E¹, E² and E³)$, spin-orbit $(\xi_4f)$ and configurational interaction (\alpha)) are evaluated. Spectral intensities for various absorption bands of $Er³⁺$ doped sodium borate glass are calculated. Using Judd-Ofelt intensity parameters $(\Omega₂,\Omega₄, \Omega₆)$, radiative transition probabilities (A), branching ratios (\beta) and integrated absorption cross sections (\Sigma) are reported for certain transitions. The radiative life times $(\tau_R)$ for different excited states are estimated. From the fluorescence spectra,the emission cross section $(\sigma_p)$ for the transition, $⁴I_13/2 -> ⁴I_15/2$ is reported.