COPPER-ION POINT DEFECTS IN THE PHOTOREFRACTIVE MATERIAL (KXNA1-X)0.4(SRYBA1-Y)0.8NB2O6

摘要: We show that Cu ions doped in (${\mathrm{K}}_{\mathit{x}}$${\mathrm{Na}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${)}_{0.4}$(${\mathrm{Sr}}_{\mathit{y}}$${\mathrm{Ba}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${)}_{0.8}$${\mathrm{Nb}}_{2}$${\mathrm{O}}_{6}$ (KNSBN) form two energy levels the band gap, which increase effective charge-combination-center concentration ${\mathit{N}}_{\mathrm{eff}}$. The two-wave coupling gain and response speed of KNSBN crystals are increased while photoconductivity effects a dc field on photorefractive properties reduced. Self-pumped phase conjugation (SPPC) experiments have revealed wavelength dependence. SPPC time at ${\mathit{e}}^{\mathrm{\ensuremath{-}}1}$ level can be shortened to 200 ms.