Holographic Image Storage with a 3-Indoly-Benzylfulgimide/PMMA Film

Abstract

Fulgide is well-known as a thermally irreversible organic photochromic compound [1,2]. It is one of the important materials in the field of optical signal processing and optical storage. Focusing on the holographic storage applications of 3indoly-benzylfulgimide/PMMA film, in this chapter include the following themes. In section 2, first the Fulgide, photochroism and photo-induced anisotropy are introduced. Then the spectra and kinetics of the photochromic and photo-induced anisotropic properties of 3-indoly-benzylfulgimide/PMMA film were studied. In section 3, the applications of ordinary holography and polarization holography of fulgide film were studied, which were respectively based on the photochromic and photo-induced anisotropy properties. The properties of holographic recording such as diffraction efficiency, spatial resolution and optimal exposure were measured. In section 4, the holographic optical image storage was realized in a 3-indolybenzylfulgimide/PMMA film by using different kinds of holographic storage techniques, e.g., transmission-type holographic recording and reflection-type holographic recording, reference beam reconstruction and phase conjugated beam reconstruction, Fraunhofer holographic recording and Fourier-transform holographic recording, different kinds of polarization holographic recording ( i.e. parallel linear polarization holographic recording, orthogonal linear polarization holographic recording, parallel circular polarization holographic recording and orthogonal circular polarization holographic recording etc.), and collinear holographic storage technology etc. The diffraction efficiencies and diffractive images’ signal-to-noise-ratios (SNR) of different kinds of holograms were compared. The storage density of 2×108 bits/cm2 was obtained in the Fourier-transform holographic data storage by using orthogonal polarization holographic recording, which had a greatly improved signal-to-noise ratio of the diffraction image. And different kinds of multiplexing holographic storage (like polarization multiplexing, circumrotation multiplexing and angle multiplexing) and holographic interferometer were realized in the film.