BaTiO 3 Developments: 1) Seeded Stimulated Photorefractive Scattering, And 2 ) Photoluminescence

in variously-doped and undoped crystals can be used to discriminate between photorefractively active and inactive impurity and defect centers. as are shown in the figures2, are common contaminants in both Hughes-grown and Sandersgrown BaTiO, crystals. The Sanders-grown crystal was from boule #69, and the Hughes-grown crystals included both nominally-undoped crystals and crystals purposely doped with CO, Fe, Mn, and Eu. The BaTi03:Eu spectra, Figure 3, contained Eu emission lines as well. What role, if any, do these rare earth contaminants play in photorefractive charge transport? To find the answer to this question, we have performed measurements of the steady-state and transient phase-conjugate reflectivity of both back-seeded and internally seeded, self-pumped SPS conjugators as a function of wavelength. A Ti:A120, laser, tuned from 730 nm to 930 nm, was used as the pump laser. The results of these experiments, as well as recent developments in externally-seeded' stimulated photorefractive scattering phase conjugators, will be discussed. Photoluminescence excitation and emission spectra, such indicate that the rare earths