OPN November 1997
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Acousto-Optic Tunable Filters
Neelam Gupta
Acousto-optic tunable filters are powerful tools for spectroscopy, imaging, and WDM. Gupta traces the development of these devices and discusses current and future applications. more>>
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Compact Discs
Demetri Psaltis, Douglas G. Stinson,and G.S. Kino, Tom D. Milster
With an installed base of over 100 million CD read-only memory (CD-ROM) readers and over half a billion CD audio players, the CD is easily the most successful family of optical storage systems, and in fact, one of the most successful consumer electronic products of all time. Approximately 90% of all personal computers shipped today contain a CD-ROM reader. This large installed base, plus the low cost of the disc ($.005/MB for a "one-off" recorded CD, less for a mass replicated CD) makes CD the ideal format for distributing or sharing digital data. more>>
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Holographic Memories
Demetri Psaltis, Douglas G. Stinson,and G.S. Kino, Tom D. Milster
Holographic memories, first investigated in the late-
1960s and early-70s, have made a remarkable comeback in the 1990s. Research in academia and industry
(primarily in the U.S.) has resulted in a number of
impressive laboratory demonstrations, showing that
holographic memories have the storage density, readout
speed, and fidelity required for competitive commercial
products. more>>
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Near-Field Optical Storage
Demetri Psaltis, Douglas G. Stinson,and G.S. Kino, Tom D. Milster
One disadvantage of CD-like systems is that the lens
used to focus laser light onto the recording layer must
be located some distance from the disc due to the presence
of the protective substrate. Systems that do not
have a protective substrate can use lens systems that are
essentially in contact with the recording layer. This type
of system is called a near-field system, because the electric
field of the focused spot is partially in the lens and
partially in the recording layer. A much smaller spot size
can be produced by near-field systems; thus disc capacity
can be dramatically improved. more>>