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 × 10 −9 E 0 cm 2 J −1 and 3.0 × 10 −9 E 0 cm 2 J −1 were achieved for 1.5 mm 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 kV cm −1 and of 25 cm −1 at E 0 = 3.9 kV cm −1 , respectively. The normalized PR response time under 1 W cm −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.