Electron trap liberation in MgF2 doped with Yb2+ using a two-color excitation experiment

We utilize the optical transitions of Yb2+ excited by an ultraviolet optical parametric amplifier to probe electron trap liberation in MgF2 via the observation of a photoluminescence enhancement effect induced by a subsequent infrared pulse from a free-electron laser. The temperature dependence of the enhancement suggests that we liberate very shallow traps having a depth of approximately 17 cm(-1). The observed trap spectrum is consistent with a simple model of a Coulomb trap. (C) 2012 American Institute of Physics. [doi:10.1063/1.3678630]