Photoluminescence of LiF crystal colored by a focused electron beam

The absorption, emission and excitation optical spectra of F 2 and F + 3 color centers generated in LiF through low energy (30 keV) electron beam irradiation were measured at room temperature by pumping with an Ar + laser the resulting thin colored layer. A quenching of the emission intensity of the F + 3 centers versus the pump power was observed, with characteristics similar to bulk colored crystals. The analysis of the photoemission spectra showed a new band, which has been discovered previously also in bulk crystals colored and treated in different ways. The possibility of applications of the colored ribbon for miniaturized laser devices is commented.