PHOTOREFRACTIVE PROPERTIES OF MANGANESE-MODIFIED POTASSIUM-SODIUM STRONTIUM BARIUM NIOBATE CRYSTALS

The crystal preparation, the transmissivity, and the properties of the two-beam coupling and the self-pumped phase conjugation (SPPC) of man ganese-modified potassium sodium strontium barium niobate (KNSBN) sing le crystals are reported. The Mn ions doped in the KNSBN can form a de ep energy level of 2.53 eV. The two-beam coupling gain coefficients of Mn-doped KNSBN crystal are larger than 37 and 35.3 cm(-1) for the tra nsmission and the reflecting photorefractive index gratings, respectiv ely. The very striking optical diode effect is observed in our experim ent. The maximum SPPC reflectivity is higher than 40%.