Transient Saturation Spectroscopy for measuring the lifetime of hyperfine sublevels in 167Er3+ ions doped in a silicate glass fiber

We report our observation of the high population relaxation rate β of hyperfine sublevels in ¹⁶⁷Er³⁺ ions doped in a silicate glass fiber (EDF). In contrast to the case with a crystalline Y₂SiO₅ host, we observed that the β value became two orders higher at 4 K. Furthermore, we observed the decrease in the β value with respect to the increase in the temperature from 4 K to 20 K.