In-Line Holographic Lenses

Abstract

The in-line holographic lens with high numerical aperture up to 0.55 was photochemically fabricated in the methylene-blue sensitized dichromated gelatin film by means of the specially designed optics and the carefully controlled process. The evaluation of the MTF, the focused beam profile and the diffraction efficiency was performed. Bragg and Raman-Nath diffractions occurred in the hologram were also investigated. We developed the new optical head employing the above lens and the optical disk player equipped with this head and succeeded in playing back the video and PCM audio signals with the good signal-to-noise ratio.