Wideband holographic recorder

Holographic disk with high data transfer rate: its application to an audio response memory

This paper describes a memory realized with a high data transfer rate using the holographic parallel-processing function and its application to an audio response system that supplies many audio messages to many terminals simultaneously. Digitalized audio messages are recorded as tiny 1-D Fourier transform holograms on a holographic disk. A hologram recorder and a hologram reader were constructed to test and demonstrate the holographic audio response memory feasibility. Experimental results indicate the potentiality of an audio response system with a 2000-word vocabulary and 250-Mbit/sec bit transfer rate.

PLZT spatial light modulator for a 1-D hologram memory

A 100-bit slitlike aperture array spatial light modulator has been developed using 8.8/65/35 PLZT for a high-bit-density 1-D hologram memory. The most desirable characteristics, such as distortion-free diffraction-limited Fourier transform patterns and good uniformity of displayed bit patterns over 100 bits, have been realized. The lowest SNR was 86, and rise time and fall time have been 30 microsec and 8 microsec, respectively, at 190-V halfwave voltage. One-dimensional holographic storage experiments have been successfully performed using this PLZT spatial light modulator.

Development of thermoplastic-photoconductor tape for optical recording

We report in this paper the continuous coating of the thermoplastic-photoconductor medium on a transparent polyester tape base for holographic optical data recording. The tape performance is evaluated in a moving transport at speeds up to 15 ips (38.1 cm/sec). Uniform diffraction efficiencies for both 2-D and 1-D holograms have been demonstrated. Furthermore, we have recorded complex 1-D holograms on the moving tape with high quality readout, and we have also made complex spatial filters on the tape which produce good correlation results in a coherent optical data processor. Numerous material factors affecting the performance of the tape in a moving tape system have been defined and investigated. Factors such as coating uniformity, electrode reflectivity, photoconductor reciprocity, the pressure endurance of the surface relief, and the tape noise are singled out for discussion in this paper.

Transparent electrophotographic films for optical data storage applications

The experimental evaluation of a transparent electrophotographic (TEP) film is reported. The objective of the evaluation was to determine the suitability of TEP films for optical data storage applications, especially those using holography. The characteristics of TEP films that motivated the evaluation are good sensitometric and holographic recording responses, relatively high resolution, and a number of attractive applications properties, e.g., long shelf life, good environmental integrity, and exceptional image permanence. In addition, TEP films have an add-on capability. A general description of TEP films is given, and sensitometric and holographic data are summarized for an experimental TEP film.

High speed holographic digital recorder

Concepts, feasibility experiments, and key component developments are described for a holographic digital record/reproduce system with the potential for 1.0 Gbit/sec rates and higher. Record rates of 500 Mbits/sec have been demonstrated with a ten-channel acoustooptic modulator array and a mode-locked, cavity-dumped argon-ion laser. Acoustooptic device technology has been advanced notably during the development of mode lockers, cavity dumpers, beam deflectors, and multichannel modulator arrays. The development of high speed multichannel photodetector arrays for the readout subsystem requires special attention. The feasibility of 1.0 Gbits/sec record rates has been demonstrated.