A polarized fast luminescence of LiB3O5 single crystals excited by synchrotron radiation

The paper presents the results of study of luminescence for the oriented LiB3O5 crystals under excitation with a polarized synchrotron radiation over the X-ray spectral range. It was revealed that LiB3O5 crystal exhibits a polarized fast luminescence with the complex broad band peaked in the spectral region from 3.5 to 4.2 eV. Time-response of luminescence demonstrates both the fast exponential component with the time-constant of 1.2±0.2 ns (300 K) and 1.3±0.3 ns (80 K) and inertial components in the microsecond time-range. The intensities of the elementary sub-bands as well as the intensity of the fast component depend on orientation of the exciting electrical vector Eex to the main crystallographic 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 excitation of the luminescence centers in LBO through the resonant energy transfers inheriting the initial polarization from the polarized synchrotron radiation.