Slashdot Mirror
Pioneer Ultraviolet Laser Promises 500GB Discs
No Fortune writes "Here's an article indicating that Pioneer is developing an ultraviolet laser for data storage. Since the wavelength of ultraviolet lasers is shorter than the wavelength of blue lasers, the beams are finer and they can pack more data into per square inch. This gives a data rate 20 times more than the blue laser Blue-ray disk."
For the benefit of any idiot who thinks parent poster is serious, allow me to point out that your current CD and DVD players use Infra-Red laser diodes, which are also invisible and dangerous. That's why your CD player will often have a warning on the outside.
Dr. Pantyhose is a known Troll. Please don't try to engage him in discussion, that's what he wants. Well, that and karma.
Ce n'est pas un vrai mouvement de robot!
The limit is defined by the amount of power you can reasonably draw from your system to generate the radiation. Higher frequency means more power is required to generate a 'low-power' beam.
The other limit is finding a suitably reflective material that is cheap enough to be used as media. X rays pass easily through plastics, and they are absorbed by lead. Gamma rays pass through most kinds of material. You need something that reflects well, and doesn't absorb the radiation, that can also be used to store distinct states and be mass produced easily.
This is not a sig.
So I assume the breakthough is that they made it into a diode? UV lasers exist now:t m
http://www.laserinnovations.com/sabrefred.h
Better yet cover them with this.
It should fix the knicks and scratches problem.
X-Rays, on the other hand, are much easier. X-Ray lasers have existed for some time (though they tend to be on the bulky side) and lenses that can focus X-Rays are used.
However, with X-Rays, you can build systems that don't just rely on reflection (as per traditional optic media). There is a phenominon called X-Ray Fluorescence, in which an atom, when struck by an X-Ray of the right frequency, emits electrons of a specific energy.
A disk using such a system would need to be layered and etched multiple times, which would make it impossible to write on any kind of domestic scale. However, it would mean that you could have maybe fifty or so "layers" to the disk.
You couldn't use this to read at the atomic level, but you could use it to determine the quantity of a given isotope. This would let you increase the effective density still further.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Something along these lines could help with media dropouts. You can build these files with as little or as much redundancy as makes you feel comfortable. Of course, if Timmy Toddler uses the medium as a frisbee or the dog eats it, you're still SOL.
I too have felt the cold finger of injustice.
People more versed in physics than I am can answer this:
:)
The lasers used for optical media keep on progressing to higher frequency light, which is better able to resolve things. Where is the likely end for optical media?
Past ultraviolet light is x-rays and gamma rays I think... Will they be used for optical media? They are known as "dangerous", but perhaps in low power situations they aren't too bad? Or, you could just have the optical drive shielded in lead
Microscopes haved moved past light, into "electron microscopes", which used streams of electrons to resolve things that light cannot. Will that be possible with our optical media techniques?
It would be so low power that it wouldn't be dangerous. But, x-rays and gamma rays don't act like normal light. They would just coast right through a plastic disc. You wouldn't be able to reflect it off of lead like a normal disc, either. Perhaps an xray disc might be more like a shadow mask. Alternating lead/no lead.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
There were magazine articles about blue laser cd-rom drives in the early-mid 90's and it's only just starting to come out.
Parent comment always gets modded up on slashdot with regards to optical media... here goes.
Redundancy and error correction will make up for any casual-use scratches ("casual" meaning you generally take care of your CDs, but perhaps don't always put them back in their cases immediately or whatnot). The more space, the more error correction you have in the form of redundancy and things such as parity, not to mention faster chips allowing for interpolation to fill in any gaps that may exist.
Also, don't forget the way the data is physically read is AROUND the disc, so in order to do any real sort of damage would be to have large scratches also going around the disc. This is why when cleaning discs, you should always clean from the inside of the disc to the outside, NOT going around it.
Regarding your DVD problems, have you tried cleaning your lens properly (not trying to be a smartass, disc-read problems are more often than not a function of the laser)?
So in short, you have nothing to worry about (this also assumes that you don't buy a KMart brand unit with a poor laser). With more space, we get better error correction and opportunities for redundancy, and the physical nature of the media makes it more resiliant to every-day scratches (just remember how the data is physically read and it becomes apparent). If it wasn't for whatever strange reason, then the engineers who spend years putting the technology together would accomodate for that.
Hopefully that clears some of it up.
In magnetic recording devices, the data density limited by either the size of the head or the size of magnetic domains in the platter material. As I understand it, at this time the platter is the limiting factor. The density on a modern HD platter exceeds that of a CD or DVD disc.
With optical storage, the data density is limited by the wavelength of the photons interacting with the medium, as well as the detail of the medium itself. A DVD can store more data than a CD because of the smaller wavelength of its red laser. The blue laser in blu-ray discs as an even smaller wavelength, and yields even more data per disc. Obviously, the media need to be altered to accept the higher data density - and photon energy for recordable discs.
The size of the laser unit itself is not really relevant, as its output is focussed into a tiny point on the recording layer.
At 70 nm between disc pits, you're starting to reach the quantum limit (that's the UV laser). Simple dust particles too small for your eye to see could cause megabytes of data loss on reading and writing. I'm assuming they're either working out the problems (vacuum sealed discs) or already solved them. But I wouldn't hold my breath waiting for the next "disc" using x-rays or gamma rays.
:)
For instance, at the energies X-rays, you're now talking electrons. The chance of an error increases enormously. The media would have have to be made of something akin to diamond,or another type of crystal so that the diffraction of the rays could be interpereted as data. And even then, random "tunneling" and such could cause data issues. You'd also have to keep the radiation energy low, or encase the drive in a lead sarcophagus. And forget about gamma ray discs.
I think the next big step will be solid state (crystal matrices or the like) and not disk based. Though if they do work out the dust/scratch problem on the UV discs I'd probably get one.
~X~
~X~