Energy transfer processes and Ho3+: I55 level population dynamics in chalcohalide glasses

Population dynamics of Ho3+: I55 levels doped in chalcohalide glasses were investigated through the analysis of energy transfer processes. Excitation migration (I55, I85 → I85, I55) predicted from the Dexter model dominated over the cross relaxation (I55, I85 → I75, I75). Depopulation of the I55 level due to upconversion was suppressed when the 890 nm excitation source was used since this pump wavelength significantly depressed the excited-state absorption transition from the I55 level. The dominant energy transfer channel leading to the depopulation of the I55 level is the energy transfer upconversion process between Ho3+ ions.