Thermally-grown thin films and bulk crystals were bombarded with swift heavy ions in order to investigate color-center production and their transformation into more complex defects. The samples were characterized by their optical absorption and photoluminescence under 442nm HeCd laser excitation at room temperature. When compared with thin films, for a given electronic excitation and ion fluence, it was found that bulk crystals exhibited relatively intense photoluminescence bands at about 530 and 665nm; corresponding to the emissions of F3+ and F2 centers, respectively.

Optical Absorption and Photoluminescence Studies of Thin Films and Bulk Crystals of LiF under Swift Heavy Ion Irradiation. F.Singh, A.Sarma, R.M.Montereali, F.Bonfigli, G.Baldacchini, D.K.Avasthi: Radiation Measurements, 2003, 36[1-6], 675-9