Energy transfer processes and Ho3+: 5I5 level population dynamics in chalcohalide glasses

Population dynamics of Ho3+: I-5(5) levels doped in chalcohalide glasses were investigated through the analysis of energy transfer processes. Excitation migration (I-5(5),I-5(8)-> I-5(8),I-5(5)) predicted from the Dexter model dominated over the cross relaxation (I-5(5),I-5(8)-> I-5(7),I-5(7)). Depopulation of the I-5(5) 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 I-5(5) level. The dominant energy transfer channel leading to the depopulation of the I-5(5) level is the energy transfer upconversion process between Ho3+ ions.