In this paper we investigate the mechanisms for electron trapping, following photoionization of Sm2+ in γ- and non-γ-irradiated samples of Sm-doped CaF2. Using linear absorption, fluorescence and site-selective coherent anti-Stokes Raman excitation spectroscopy, we show that the electron traps in non-γ-irradiated CaF2 : Sm are small clusters of trivalent Sm ions. In the γ-irradiated samples, we observe the formation of self-trapped holes after photoionization, which provides us with additional evidence for the existence of self-trapped hole pairs in γ-irradiated rare-earth-doped CaF2. © 1998 Elsevier Science B.V. All rights reserved.
