Population relaxation induced by the Boson peak mode observed in optical hyperfine spectroscopy of ~(167)Er~(3+) ions doped in a silicate glass fiber

摘要

We demonstrate transient saturation spectroscopy for ~(167)Er ~(3+) ions doped in a silicate glass fiber cooled at 2:5-30K to measure the population relaxation time t_1 of the hyperfine sublevels. The observed t_1 value is 3:1 ms at 4K and we observe anomalous temperature dependence whereby t_1 becomes rather longer with heating from 4 to 30K. We can regard the population relaxation as a result of the Raman scattering of the Boson peak mode (BPM) peculiar to a silicate glass by the 4f-electrons of the ~(167)Er~(3+) ions. We can attribute the anomalous temperature dependence to the suppression of the Raman scattering by thermal hopping of the localized BPM.