Three-dimensional optical data recording

There are two ways to achieve higher density the extension of the data-recording space in the axial direction, and the reduction of bit size. In this chapter, we describe a method for overcoming the density limit, namely, introduce an additional axial dimension in the recording process. " " The z or longitudinal axis is used in addition to the surface dimension (x—y space) of conventional optical memory. The data are thus written not on the material surface but within the three-dimensional (3D) thick volume. The media that can be used are photochromic materials. ... 

A photorefractive polymer consisting of DMNPAA, TNF, ECZ, and PVK has been used for erasable/rewritable three dimensional bit optical data storage under two-photon excitation. A three dimensional bit density of 5 Gbits/cm(3) is achieved by pulsed beam illumination at an infrared wavelength of 800 nm in the recording process. 

Many lay cell biologists use confocal imaging to refer to anything from a simple digital recording of a single focal plane to a full three-dimensional data By fluorescence LM, 1 mean use of a compound light (optical) microscope equipped for epifluo-... 

This three-dimensional distribution of the fluid density can be resolved by recording with the optical setup several projections in different directions through the flow and processing the obtained data with the methods of computer tomography. If the flow has rotational symmetry, one projection only is sufficient, and the axisymmetrically distributed fluid density can be determined by applying to the data an inversion scheme Abel inversion). 

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