OPTICAL-PROPERTIES OF PHOTOSTIMULABLE NEAR IR CENTERS IN BAFCL SINGLE-CRYSTALS PRODUCED BY 2-PHOTON EXCITATION

The stable and photostimulable F-aggregate centers, besides the alread y established isolated centers, located in the near IR region in BaFCl single crystals are reported. These F-aggregate centers are producibl e by two-photon excitation and the production rate can be enhanced by monovalent doping like incorporating K+ in BaFCl. The F-aggregate cent ers in BaFCl have been characterised by their growth behaviour, room t emperature stability, optical bleaching, emission and the temperature dependence of the PSL lifetimes. It is a first time demonstration as a pplied to BaFCl single crystals to produce F-aggregate centers more ef ficiently by using the fourth harmonic of a Q-switched Nd:YAG laser as compared to X-irradiation.