Pair processes inCsCdBr3:Er3+: A study by up-conversion and excited-state absorption of efficient uv and blue anti-Stokes emissions

Excitation in the ${}_{}{}^4{}_{}{}^{}$ ${\mathit{S}}_{3/2}$, ${}_{}{}^4{}_{}{}^{}$ ${\mathit{F}}_{7/2}$, or ${}_{}{}^4{}_{}{}^{}$ ${\mathit{F}}_{5/2}$ levels results in efficient anti-Stokes emissions between 25 300 and 32 600 ${\mathrm{cm}}^{\mathrm{-}1}$. Up-conversion is due to an energy transfer in symmetric pairs, which are the dominant center in this compound. To determine transfer rates for this mechanism, transients of ${}_{}{}^4{}_{}{}^{}$ ${\mathit{D}}_{5/2}$ and ${}_{}{}^4{}_{}{}^{}$ ${\mathit{G}}_{9/2}$ levels have been studied using excited-state absorption in the ${}_{}{}^4{}_{}{}^{}$ ${\mathit{F}}_{9/2}$ state. Detailed excitation spectra have also been recorded for these high-energy levels. A close examination of fluorescence dynamics for these various excitation paths showed the importance of competing pair relaxations in this system.