OPTICAL SPECTROSCOPY PROPERTIES OF BALIF3 DOPED WITH NI-2+

The basic optical properties of a new perovskite crystal, BaLiF3, dope d with Ni2+ are reported. We have identified several absorption bands belonging to the Ni2+ in an octahedral site by the direct adsorption s pectrum as well as by the excitation spectrum. The main absorption ban d peaks at 1180 nm with a DELTAE/E almost-equal-to 30%, showing very w ell defined sharp lines, at low temperature, due to spin-orbit splitti ng of the excited state. By pumping in any of the absorption bands, a strong emission band peaking at 1.5 mum (DELTAE/E almost-equal-to 20%) is observed, with a decay time at room temperature of 3 ms. Besides t he 1.5 mum emission band, two other bands were observed, peaking at 48 0 and 740 nm. All the observed energy transitions are in good agreemen t with the Tanabe-Sugano model and the measured cross-sections are in the range of the expected ones for allowed magnetic dipole transitions .