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HankScorpio-vs-World t1_j31bb27 wrote

I think the track density is actually more limited by the reading method than the stamping method.

The laser focus is the limiting factor, had to move from a low frequency red laser for a normal CD, to a high frequency blue laser (it’s actually violet) to get the data capacity higher for blue Ray. I believe “multi layer reading” is already being exploited for 4K use on a 5” disc which takes advantage of even finer stamping methods.

I think 25gb is the standard single layer capacity and the current disks in use are dual layer at 50gb… this is expected to rise with XL disk players/writers where the capacity is stretched to 128GB using 4 layers on a single disc using even finer laser targeting/focussing methods.

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HankScorpio-vs-World t1_j31cwia wrote

Link to Wikipedia picture of the dot spacings on blue Ray discs https://en.wikipedia.org/wiki/Blu-ray#/media/File:Comparison_CD_DVD_HDDVD_BD.svg

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ChronoX5 OP t1_j32ea85 wrote

That's a helpful picture. Thank you! It blows my mind that they can manufacture physical bumps smaller than the wavelength of light.

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rudy21SIDER t1_j34ap9g wrote

Light wavelength can be as big as the empire state ( radio) or as small as a Planck 's length (lethal radiation) so there is a big "not impressive" margin.

Still very impressive precision in nanometers but we gave way smaller things (chip manufacturering).

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Insertsociallife t1_j35wv04 wrote

Couldn't the wavelength of light considered to have a limit at infinity? If frequency has a limit at 0, it could still multiply to c, right?

Edit - should clarify, calc definition of limit, infinitely close to but is never the value it's limited by

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katt2002 t1_j32p5le wrote

Is that limited to visible light only? How about wavelength shorter than ultraviolet? X-ray, gamma? They are also electromagnetic wave, right? Same question for tools used to manufacture CPU chips.

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HankScorpio-vs-World t1_j32sz9q wrote

It’s about safety and cost when it comes to data storage… yes shorter wavelength emission/reading systems are possible but are they necessary. At the moment we are yet to have a video encoding system that needs a disc bigger than 128GB for a movie. Chances are by the time we do it will be streamed via the internet and a physical disc will be redundant.

But who knows what future tv formats will need for storage, when I was a kid a 240line VHS tape was astounding now 1080 lines is considered old technology.

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