Manganese-doped yttrium orthoaluminate: A potential material for holographic recording and data storage

Optical properties of manganese-doped yttrium orthoaluminate crystals (Mn:YAlO₃), grown by the Czochralski technique, are reported. Luminescence and absorption spectra indicate the presence of Mn⁴⁺ ions in as-grown crystals, and Mn³⁺, Mn⁴⁺, and Mn⁵⁺ ions simultaneously in photoexcited crystals. A permanent diffraction grating, erasable by heating, was obtained in the crystals with diffraction efficiency of more than 50% at 514.5 nm reading wavelength and 1--2 % in 632--930 nm wavelength range. Reading at wavelengths longer than 630 nm did not damage the recorded grating. The electro-optical effect observed in the photoexcited crystals implies that manganese ions disturb the YAlO₃ crystal structure so that it becomes noncentrosymmetric.