We propose a bacterial detection scheme which uses no biochemical markers and can be applied in a Point-of-Care
setting. The detection scheme aligns asymmetric bacteria with an electric field and detects the optical scattering.
The holographic disc is a high capacity, disk-based data storage device that can provide the performance for next generation mass data storage needs. With a projected capacity approaching 1 terabit on a single 12 cm platter, the holographic disc has the potential to become a highly efficient storage hardware for data warehousing applications. The high readout rate of holographic disc makes it especially suitable for generating multiple, high bandwidth data streams such as required for network server computers. Multimedia applications such as interactive video and HDTV can also potentially benefit from the high capacity and fast data access of holographic memory.
The issue of interfacing holographic memory with an electronic processor is discussed. The high speed and parallel access of 2D, page formatted optical data from holographic memory can be utilized to reconfigure an electronic processor at a rate much faster than traditionally available. This new technique could be the stepping stone to a new class of high performance device for a variety of image/signal processing tasks. We will first give a review of the holographic memory activity at Holoplex, in particular, our research on holographic optical disk as a read-only memory device. We will then discuss the optical architecture for interfacing an optical ROM with a programmable gate array processor.
Holographic memories can be read-out either with the reference or the signal beam. Reference beam read-out reconstructs the stored data whereas signal beam read-out performs a search of the stored data base. This dual mode of holographic memories is explored for the various methods that have been developed for multiplexing holograms.
Shift multiplexing is a holographic storage method implemented with spherical wave reference beams. We present the main properties of shift multiplexing, compare it with angle multiplexing, and describe the design of a holographic 3D disk system that is capable of storing 12.4 bits/micrometers <SUP>2</SUP> using this method.
We have achieved a surface density of 10 bits/micrometer<SUP>2</SUP> (6.5 Gbits/in<SUP>2</SUP>) with an experimental holographic storage setup, using DuPont's 100 micrometer thick photopolymer as the recording medium. Its performance characteristics in terms of access rate and signal-to- noise-ratio are described. Furthermore, a simple holographic 3D disk system with high surface density (10 bits/micrometer<SUP>2</SUP> using a 100 micrometer thick recording material) and an architecture similar to compact disks is shown.
Holographic techniques and materials have matured sufficiently to allow high capacity in practical systems. We demonstrate a holographic memory with storage density of 10 bits/micrometers <SUP>2</SUP>. Novel techniques, such as shift multiplexing, can be used to attain even higher capacity with simpler implementation.
We have recently developed a new method of multiplexing volume holograms which we call peristrophic multiplexing. The method involves rotation the material, or equivalently, the recording beams. Peristrophic multiplexing can be combined with other multiplexing methods to increase the storage density of holographic storage systems such as holographic 3-D disks. Peristrophic multiplexing has been experimentally demonstrated using DuPont's HRF-150 photopolymer film. A total of 295 holograms were multiplexed at a single location in a 38 micrometers thick photopolymer disk by combining peristrophic multiplexing with conventional angle multiplexing. Application of this new multiplexing method toward a 3-D holographic disk is discussed.
The recording characteristics of DuPont's HRF-150 photopolymer film are described. The application of these films for data storage using the 3-D holographic disk architecture is presented. The required system's bandwidth due to the photopolymer's limited thickness is shown to be the limiting factor of the storage capacity of these thin films and not the material's dynamic range. A new multiplexing method (peristrophic multiplexing) that significantly increases the film's capacity and changes the limiting factor from system bandwidth to material dynamic range is presented.