Photorefractive Properties of Co-Doped Potassium Sodium Strontium Barium Niobate Crystals

Abstract

Cryst. Res. Technol. 341999 3 403-407The transmissivity and the results of two-beam coupling and self-pumped phase conjugation (SPPC) experiments on Co-doped potassium sodium strontium barium niobate (KNSBN) single crystals are reported. The Co ions doped into KNSBN can form a deep energy level near 2.25 eV. The two-beam coupling gain coefficients of the Co-doped KNSBN are nearly 20 cm -1 at 2θ ≈ 37 0 for the transmission photorefractive index grating and larger than 29.2 cm -1 for the reflecting photorefractive index grating. A striking single-beam asymmetric transmission was observed. The maximum SPPC reflectivity is larger than 70% at θ = 49.7 0 for an intensity W = 77 mW, which is the largest value measured in the family of KNSBN crystals.