A POLARIZED FAST LUMINESCENCE OF LIB3O5 SINGLE-CRYSTALS EXCITED BY SYNCHROTRON-RADIATION

The paper presents the results of study of luminescence for the orient ed LiB3O5 crystals under excitation with a polarized synchrotron radia tion over the X-ray spectral range. It was revealed that LiB3O5 crysta l exhibits a polarized fast luminescence with the complex broad band p eaked in the spectral region from 3.5 to 4.2 eV. Time-response of lumi nescence demonstrates both the fast exponential component with the tim e-constant of 1.2+/-0.2 ns (300 K) and 1.3+/-0.3 ns (80 K) and inertia l components in the microsecond time-range. The intensities of the ele mentary sub-bands as well as the intensity of the fast component depen d on orientation of the exciting electrical vector E-ex to the main cr ystallographic axis Z, on the density and polarization of the exciting synchrotron radiation. The paper discusses the origin and excitation channels for the broad-band luminescence as well as mechanisms of exci tation of the luminescence centers in LBO through the resonant energy transfers inheriting the initial polarization from the polarized synch rotron radiation.