Time-resolved photoluminescence of ${\mathrm{Fe}}^{3+}$ ions in fluorozirconate glass

The optical properties of ${\mathrm{Fe}}^{3+}$ ions incorporated into fluorozirconate glass have been studied with optical absorption as well as with steady-state and pulsed photoluminescence (PL) techniques. Two separate contributions to the broad ${\mathrm{Fe}}^{3+}$ PL spectrum have been identified on the basis of distinctly different PL decay rates. The slower process (0.2 ms at 300 K) is associated with the internal transitions from the $G^4$ crystal-field-split level to the ${}_{}{}^6{}_{}{}^{}\mathrm{A}_1^{}{}_{}{}^{}$ ground state of the ${\mathrm{Fe}}^{3+}$ ion in an octahedral site. The faster process (10 μs at 300 K) has been identified with the ${\mathrm{Fe}}^{3+}$→${\mathrm{Fe}}^{2+}$ charge-transfer process. The appropriate crystal-field parameters are B=1091 ${\mathrm{cm}}^{\mathrm{-}1}$, C=2946 ${\mathrm{cm}}^{\mathrm{-}1}$, and Dq=1222 ${\mathrm{cm}}^{\mathrm{-}1}$.