Laser-induced filling and thermal filling of spectral holes in BaFCl_0.5Br_0.5:Sm²⁺

Laser-induced filling and temperature cycling experiments were conducted in the sample BaFCl_0.5Br_0.5:Sm²⁺. Under laser irradiation, the decay curve of the hole area is composed of a fast component and a slow component. In the temperature cycling curve, there are a slow decrease of the hole area from 77 to 200 K and a rapid drop above 300 K. The decay of the hole area with time at 77 k and 313 K follow a logarithmic law. Analysis of these results shows that there are two kinds of traps which govern hole burning and filling processes in the sample. One is related to some impurities or defects. Another is related to Sm³⁺ ions. The distribution of the potential well of the latter, produced by substitutional disorder, can be described by a two-level-system model.