Yukihisa OSUGI¹ and Takumi MINEMOTO²

¹Corporate Research and Development Group, NGK Insulators, Ltd., Suda, Mizuho, Nagoya, 467 Japan, ²Department of Computer and Systems Engineering, Kobe University, Rokkodai, Nada, Kobe, 657 Japan

(Received June 12, 1996; Accepted August 20, 1996)

A large-screen, real-time hologram device using Bi₁₂SiO₂₀ (BSO), which enables observation of reconstructed images by parallax vision has been fabricated. The BSO wafer size of the device was 70×70×3mm³. The wafer was dipped in silicon oil to avoid the electric discharge between the electrodes. The conditions were studied to obtain complete reconstruction from the large Fresnel volume-type real-time hologram and a uniform diffraction efficiency was obtained over the entire area including the core of the crystal. Irradiation at a level of 4 mJ/cm² yielded a diffraction efficiency of 0.5%. Binary and half-tone images were holographically recorded and reconstructed. The reconstructed images could be observed by the naked eye, including the actual depths.

Key words : hologram, photorefractive, three-dimensional display, Bi₁₂SiO₂₀, diffraction