How using shorter-wavelength laser allows more information to be stored

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Discussion Overview

The discussion centers around how the use of shorter-wavelength lasers can increase the amount of information stored on optical discs, exploring the implications of laser wavelength on data storage capacity and the effects of diffraction.

Discussion Character

  • Technical explanation
  • Exploratory
  • Debate/contested

Main Points Raised

  • Some participants note that the width of the laser beam is a significant limitation due to the diffraction effects of light.
  • One participant suggests that decreasing the wavelength of light allows for smaller pits to be created, thus enabling more pits to fit along a given length on the disc.
  • Another participant mentions that pressed discs can have two layers, and increasing laser power can allow transmission through the first layer to access the second layer.
  • It is mentioned that future data storage methods are exploring holographic 3D data storage, which is still based on optical principles.
  • One participant reiterates that shorter wavelengths lead to closer spacing of information on the disc due to diffraction patterns.

Areas of Agreement / Disagreement

Participants express various viewpoints on the relationship between laser wavelength and data storage capacity, with no consensus reached on all aspects of the topic. Some points are agreed upon, such as the impact of diffraction, while other aspects remain open for further exploration.

Contextual Notes

The discussion does not resolve the complexities of how diffraction specifically limits data storage or the implications of using different laser technologies. There are also references to future technologies that remain speculative.

Who May Find This Useful

Individuals interested in optical data storage technologies, laser applications in data retrieval, and advancements in holographic memory systems may find this discussion relevant.

ah lai
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Information is stored in a series of pits on the disc. These pits are scanned by a laser beam. An significant limitation on amount of information that can be stored on a disc is width of laser beam.

I knew why the width of laser beam is important coz diffraction effect of loght.


How using shorter-wavelength laser allows more information to be stored on disc of same size??

Any website i can refer to ? Thanks!
 
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Well for one, decreasing the wavelength of the light, allows to decrease the size of the pits, hence more will fit on a line of given length.
 
Also don't forget that "pressed" discs have two layers, by increasing the laser power, it is possible to trasmit through the first layer onto the second layer.

Try looking for DVD under wikipedia:

http://en.wikipedia.org/wiki/DVD

and "how stuff works":

http://www.howstuffworks.com/dvd.htm

Also Note that information is limited in 2d space (ok it is quasi 3d space, since we have two layers)
Future data storage is working on holographic 3d data storage (which is still optical based):

http://en.wikipedia.org/wiki/Holographic_memory

http://en.wikipedia.org/wiki/HDSS

http://www.inphase-technologies.com/
 
I was aware that it had to do with diffraction patterns that determined how much data. The shorter the wavelegth, the closer the (spiral) of information is on the disc.
 

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