Holography and Optical Storage
The term holography is composed of the Greek words holos (= whole) and graphein (= to record, to write), and thus summarizes the key aspects of its underlying principle: recording the complete wavefront of an object, i.e., its intensity as well as its pha
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Holography a 20. Holography and Optical Storage
Various approaches to increasing the areal density of optical storage systems are introduced. Next, the advantages of and approaches to volume optical recording that are currently under consideration for future generations of optical storage systems are presented. The state of the art as well as physical and technical attempts to realize holographic data storage are discussed in detail.
20.1 Introduction and History ....................... 1206 20.2 Principles of Holography ....................... 1207 20.2.1 Recording of Holograms and Wavefront Reconstruction ...... 1207 20.2.2 Classification Scheme................... 1208 20.2.3 Recording Geometries.................. 1212 20.2.4 Holography Techniques................ 1214 20.2.5 Holographic Recording Materials ... 1215 20.3 Applications of Holography ................... 1217 20.3.1 Holographic Data Storage ............. 1217 20.3.2 Holography in Archaeology........... 1217 20.3.3 Holographic Interferometry .......... 1218 20.3.4 Holography in Medicine and Biology ................................ 1219 20.3.5 Diffractive Optics with Computer-Generated Holograms ... 1220 20.3.6 Security Aspects of Holography...... 1220 20.3.7 Holographic Scattering for Material Analysis .................... 1220 20.3.8 Atomic-Resolution Holography ..... 1221 20.3.9 Neutron Diffractive Optics............. 1222 20.4 Summary and Outlook........................... 1222 20.5 Optical Data Storage ............................. 1223 20.6 Approaches to Increased Areal Density.... 1225 20.6.1 Short-Wavelength Lasers ............. 1225 20.6.2 Increased Numerical Aperture ....... 1226 20.6.3 Magnetic Super-resolution ........... 1226 20.7 Volumetric Optical Recording ................. 1227 20.7.1 Volumetric Addressing Techniques. 1228 20.7.2 Addressing by Depth of Focus ....... 1228 20.7.3 Two-Photon Absorption for Addressing of a Bit Cell ........... 1229 20.7.4 Interferometry ............................ 1229
Part D 20
The term holography is composed of the Greek words holos (= whole) and graphein (= to record, to write), and thus summarizes the key aspects of its underlying principle: recording the complete wavefront of an object, i. e., its intensity as well as its phase. Interference and diffraction phenomena are employed to record and retrieve the full information, a technique pioneered by Dennis Gabor in 1948. He was honored with the Nobel prize in Physics in 1971, reflecting the general impact of holography on modern physics. Holography plays an essential role in today’s science and industry. Relevant applications making use of its principle have been developed, including three-dimensional (3-D) displays and holographic cameras, interferometers for nondestructive material analysis, archival data storage systems, diffractive optical systems, and embossed display holograms for security features. The success of holography was made possible in particular by the availability of coherent laser-light sources. In the meantime holography has eve
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