Homodyne readout on dc-removed coaxial holographic data storage.

Multiplexing characteristics of a dc-removed coaxial holographic storage system were evaluated for what is believed to be the first time. Our dc-removed coaxial system achieved 3.5 times higher raw data density than a conventional coaxial system that involved dc recording.

Optical noise reduction for dc-removed coaxial holographic data storage.

A method of reconstructing positive and negative images from Fourier holograms recorded without the dc components is demonstrated by use of a coaxial holographic storage system. Reconstructed images are obtained by adding a phase-modulated dc component of the signal beam on reading. Contrast reversal of the reconstructed images can be achieved by reversing the readout reference pattern.

Coaxial holographic data storage without recording the dc components.

A technique of recovering the data pages from Fourier holograms recorded without the dc components is demonstrated theoretically and experimentally by use of a coaxial holographic storage system. A reconstructed image is obtained by adding a phase-modulated dc component of the signal beam on reading. The bit error rate of the reconstructed image is comparable with that for the hologram recorded with the dc component as well.

Optical noise reduction by reconstructing positive and negative images from Fourier holograms in coaxial holographic storage systems.

A technique for reconstructing positive and negative images from an identical intensity-modulated hologram is demonstrated theoretically and experimentally by use of a coaxial holographic storage system. Negative images are obtained by adding a phase-modulated dc component of signal beam on reading. By comparing positive and negative images, the bit error rate (BER) is improved by two orders of magnitude.

Thermally assisted recording of holographic gratings in semicrystalline azobenzene-containing polymers.

We examine optically induced birefringence in semicrystalline azopolymer films that are held at glass-transition temperature Tg. The birefringence increases markedly after interception of the pump beam; the saturation value depends on exposure time. In addition, the induced birefringence is completely erased by irradiation with a circularly polarized beam at Tg.