Single photon data storage

[Sceadwian]

An entire image stored in a single photon's wave function.
StarTrek eat your heart out =)

**broken link removed**

P.S. Right in my home town no less =)

 

[mkh]

how did they retrieve the image? i had understood that any measurement on such a quantum system returns only random values

 

[Sceadwian]

It doesn't delve into any details and I'm sure there are a few caveats, the only refrence in the above link was that they had to use a local oscilator to retrieve the data, some kind of interference/heterodyning effect. Even neater than the fact that they stored an image like that briefly is that they're getting better at delaying light in those kinds of cells, altering the effective speed of a light gets them that much closer to practical optical computers.

 

[mkh]

but even 5-6 years ago,they could slow light down to mere metres per second by passing photons through very high refractive index ' substances ' like bose - einstein condensates..but we are no closer to creating a quantum computer because any measurement on such a system simply collapses the superposed states.

 

[Sceadwian]

Yes, but what they're talking about is eventually being able to more or less permentantly storing photons in a storage matrix without losing any information. And a cessium vapor is a bit closer to a 'normal' substance than a bose einstein condensate, condensates like that require as close to absolute zero temperatures as physics can currently create, which makes it completly impractical excepting as experimental data. The U of R device actually performed a function, it's not wholey research.

 

[mkh]

so while they 'store' the photons,they don't interact with the environment?

 

[Sceadwian]

I have no idea how it works on the atomic/subatomic or quantum level, but the wording in the article is very clear.

Two-dimensional images carried by optical pulses (2 ns) are delayed by up to 10 ns in a 10 cm cesium vapor cell. By interfering the delayed images with a local oscillator, the transverse phase and amplitude profiles of the images are shown to be preserved. It is further shown that delayed images can be well preserved even at very low light levels, where each pulse contains on average less than one photon.

There seems to be a pretty lively discussion in the comments bellow the article.