Irradiation behavior of ytterbium-doped calcium fluoride crystals and ceramics

Abstract

We have studied the radiation resistance of CaF₂:Yb³⁺ (3 mol % YbF₃) laser ceramics and a single crystal of similar composition (3.6 mol % YbF₃) exposed to gamma rays in a ⁶⁰Co source. The unirradiated samples have been shown to be similar in spectral characteristics. Even though irradiation leads to identical valence changes, Yb³⁺↔Yb²⁺, in the single crystals and ceramics, it produces characteristic defect centers in the ceramic samples, which are responsible for the observed marked differences in the rate of valence changes and the annealing rate of radiation-induced defects.