Multilevel sensitization of Er3+ in low-temperature-annealed silicon-rich SiO2
The dynamics of Er3+ excitation in low-temperature-annealed Si-rich SiO2 are studied. It is demonstrated that Si-excess-related indirect excitation is fast (transfer time tau(tr)< 27 ns) and occurs into higher lying Er3+ levels as well as directly into the first excited state (I-4(13/2)). By monitoring the time-dependent Er3+ emission at 1535 nm, the multilevel nature of the Er3+ sensitization is shown to result in two types of excitation of the I-4(13/2) state: a fast excitation process (tau(tr)< 27 ns) directly into the I-4(13/2) level and a slow excitation process due to fast excitation into Er3+ levels above the I-4(13/2) level, followed by internal Er3+ relaxation with a time constant tau(32)>2.3 mu s. The fast and slow excitations of the I-4(13/2) level account for an approximately equal fraction of the excitation events: 45%-50% and 50%-55%, respectively.
Applied Physics Letters
"Multilevel sensitization of Er3+ in low-temperature-annealed silicon-rich SiO2" (2008). Faculty Bibliography 2000s. 934.