Enhanced photorefractive properties of paraelectric potassium-lithium tantalate-niobate by manganese doping

Paraelectric potassium-lithium-tantalate-niobate, or KLTN, crystals have been grown with two different Mn concentrations: 0.25 and 0.5 mol%. Detailed investigations have been made on the photorefractive ( PR) properties of the as-grown crystals by the two-wave mixing technique. High diffraction efficiencies of 90% and 62.5% and PR sensitivities of 1.0 x 10(-9)E(0) cm(2) J(-1) and 3.0 x 10(-9)E(0) cm(2) J(-1) were achieved for 1.5mm thick Mn(0.25) : KLTN and Mn(0.5) : KLTN, respectively. The measured two-wave mixing gains for 0.25 mol% and 0.5 mol% reached large values of 27 cm(-1) at the external field of E(0) = 3.4 kVcm(-1) and of 25 cm(-1) at E0 = 3.9 kVcm(-1), respectively. The normalized PR response time under 1Wcm(-2) illumination is less than 1 s at 532 nm. It is shown that Mn can effectively enhance the PR properties of KLTN which is a very promising ideal material for electroholographic applications.