Browsing by Author "Sainov, V"

Now showing 1 - 2 of 2

Light-induced properties of Ru-doped Bi12TiO20 crystals
(2003-11-01)
Marinova, V
;
Lin, SH
;
Sainov, V
;
Gospodinov, M
;
Hsu, KY
Absorption, light-induced absorption, photoconductivity and dark conductivity measurements are performed on Bi12TiO20 (BTO) crystals doped with different concentrations of ruthenium. It is found that a higher ruthenium addition shifts the optical absorption to the near-IR spectral region in comparison with non-doped BTO crystals and the absorption changes increase with increasing Ru content. The dark conductivity follows the Arrhenius law with an activation energy of 0.89 eV. From the measured light-induced absorption and nonlinear photoconductivity the participation of a shallow level in the charge transport mechanism in Ru-doped BTO crystals is suggested. Highly Ru-doped BTO samples possess infrared sensitivity and holographic gratings are successfully recorded at 790 and 825 nm, respectively.
Optical and holographic properties of Bi4Ge3O12 crystals doped with ruthenium
(2003-10-01)
Marinova, V
;
Lin, SH
;
Hsu, KY
;
Hsieh, ML
;
Gospodinov, MM
Bi4Ge3O12 single crystals doped with different concentration of Ru were grown by the Czochralski technique. Optical absorption bands were induced by illumination with ultraviolet light at room temperature. The absorption coefficient values increased with increasing ruthenium concentration. The induced photochromic effect was completely reversible: all samples recovered their transparency after thermal treatment. Preliminary holographic recording experiments showed a fast response time and a relatively slow erase time during the reading process. (C) 2003 Kluwer Academic Publishers.