Thread: Holographic crystal.

Ok, so right now, I have been in a conversation about holographic crystals. The question that was asked, is why does a crystal of this kind, when broken into a few pieces, retain the original data of the whole? In other words, if you break a crystal like this with, say, a picture of your family on it, it will replicate that same picture on all the different shards in perfect quality. (I posted it here because I did not now where else to post it). Thanks.

HowStuffWorks "How Holographic Memory Will Work"

Originally Posted by WaterWalker

Ok, so right now, I have been in a conversation about holographic crystals. The question that was asked, is why does a crystal of this kind, when broken into a few pieces, retain the original data of the whole? In other words, if you break a crystal like this with, say, a picture of your family on it, it will replicate that same picture on all the different shards in perfect quality. (I posted it here because I did not now where else to post it). Thanks.

Unfortunately it is not perfect quality, you loss some resolution with a smaller piece of a a broken larger hologram. The small the piece the fuzzier the hologram becomes.

@Neverfly - Thanks for the reply. But I have seen that page before. And that only describes how the holographic storage medium works, and how data is stored and recovered. It doesn't quite answer the question.

@Darkhorse - That would be true. However, as I understand the question, the data bits themselves propogate as-is through the broken pieces. And this is what is not understood. How does it do that?

I don't know whether it does, I personally don't think it does, but the other guy seems to think it does. Any clarification on this?

I think part of the problem is that the thing you'd like to know why it happens doesn't happen.

With certain forms of Holographic Memory, this can happen. This is because the hologram is created by a series of inscribed cubes, each with the whole picture and a facet of each picture for its position in the whole etched into various sides. I could be wrong and welcome correction, but I'm under the impression that no such things have currently been made- only speculated about.

But a Hologram crystal does not stack layers of data. It's simply etched with a laser and if broken, you'll only see the etchings in the broken piece and not the whole picture.

Ah. Ok. So it won't give perfect replicas of data in smaller pieces of the crystal, if the crystal were to be broken?

Originally Posted by WaterWalker

Ah. Ok. So it won't give perfect replicas of data in smaller pieces of the crystal, if the crystal were to be broken?

That would seem to negate the value of a holographic storage medium if the data is duplicated throughout the crystal. It would vastly reduce the amount of data it would be able to hold one would think.

Originally Posted by WaterWalker

Ah. Ok. So it won't give perfect replicas of data in smaller pieces of the crystal, if the crystal were to be broken?

Not that I know of. I'm sorry, I should have read the O.P. better. I thought you were asking about Holographic memory, which can show redundancies if broken down.
The reason why you would want to do that is to be able to store a lot of information that even if part of the storage is destroyed, allows for very easy recovery of the entirety.

I think it is equivalent to a Fourier transform. At least, you certainly need to use a Fourier transform if you want to calculate the hologram of an image.

If you transform a single frequency to the time domain you get something spread out across all of time. If you have something that is limited in time, it will spread out to a range of frequencies in the frequency domain.

So a single bit in the image domain is spread out across the entire hologram domain. (Or something like that ...)

The primary benefit of holographic memory as I understand it is that the density is much greater than magnetic memory and it the has potential to be extremely fast access. The theoretical limit of storage would be dependent on the wavelength of light used to record the information. In reality it would be much greater than that becuase of limitations with the materials used to store the image. With magnetic media and solid state media there are bottleneck when writing to the device. Magnetic media has moving parts and solid state has memory addressing delays. Holographic memory has the potential to be written at the speed of light, which will move the bottleneck from the storage arena to the processing arena. Additionally holographic memory can have data written and read in parallel by using different wavelengths of light.

The media still needs to be taken care of, breaking it will result in a loss of data.

With a holographic picture, the image will appear in all the broken pieces, however the smaller the broken piece the less fidelity you will get. The picture will become fuzzier and the depth of field narrower the small the piece gets. For some information, this would not be noticeable right away, the brain is very forgiving about what it "sees" . For binary data however this will mean a noticeable loss of information.

The data could be stored in several locations (or wavelengths?) which would result in data redundancy. This redundancy would allow the re-creation of the missing data. Most likely this duplication would use the same technology that we use today called RAID (redundant array of independent disks), instead of a disk it would just encode the data in different wavelengths. This will still only be 100% recoverable if there is a good copy somewhere on the device. Even with the duplication of data the storage capacity will be very large compared to what we have now (if they can make it work).

But no matter what, if you break a hologram you will lose information. How much you lose and if you can recover the original data depends on your encoding not on the media.