Stunning advance in bandwidth utilization!

[GreyGeek]

In the New Journal of Physics an article was published yesterday which shows a video demonstrating a technique of "twisting" the orbital angular momentum of a specific frequency of radio waves such that an unlimited number of radio channels (voice, or video) may use it. A video explains the technique and shows a demonstration of it. It is simply amazing.

http://iopscience.iop.org/1367-2630/14/3/033001/article

[Ole Juul]

Thanks for that GG.
We all thought that modems had reached a limit and then there was a breakthrough in modulation technique. This looks like the same kind of thing, though their "historical" promotion is a bit suspect. The concept is a little difficult to fathom, and of course this is the "early days" of it's development, but I wonder about reflections in the real world. Wireless may not be the best place for this. I've been studying commercial broadcast propagation lately so I would note the twisting of FM signals that make vertical and horizontal polarization a moot point despite being much discussed by broadcast engineers. Anyway, we'll see how this spiral concept gets applied in the future. I'll certainly be watching for development.

[GreyGeek]

The video showed the modified parabolic dishes they used to transmit the signals but they had smeared the segments of the dish which had the modification. Amazingly, or stupidly, they had photos which showed what they did. It "looks" like they cut the dish from the center to the rim, and then raised up one side of the cut by a couple of cm or so. The receiving antenna was "tuned" by leaving one side of the horizontal dipole pointed at the transmitting dish, and using a worm gear to slowly turn the other side of the dipole in the horizontal plane away from the disk. As it was turned it passed through both channels, first showing the picture, then the bar pattern.

I'm wondering of a receiver dish of the same construction as the transmitter could be rotated instead of using a dipole?

[SteveRiley]

Far out. Thanks for the link.

But until someone figures out how to violate the laws of physics, we'll always be stuck with latency

[GreyGeek]

Far out. Thanks for the link.

But until someone figures out how to violate the laws of physics, we'll always be stuck with latency

If latency is a function of utilization by multiple users, the idea that you could create a channel of your own is attractive from a bandwidth point of view.

[SteveRiley]

Latency is how long it takes for datagrams to reach their destinations. Electrons and photons don't move instantaneously, you know.

[woodsmoke]

There is stuff about this that looks good. The "math" seems to hold.

But, when I see a term like "vortices" it makes me uneasy.

woodsmoke

[GreyGeek]

Oh, THAT law!!!

Ya, that one is a stickler. It makes the possibility of communicating at distances exceeding Jupiter too painstakingly slow to be practical. Between stars, impossible. We and our EMR are stuck in this solar system.

(I thought you were referring to signal collisions. If yours is the only signal on a channel there won't be any collisions.)


@woodsmoke, the drawing of a vortices's is misleading. The Orbital Angular Momentum is a quantum property, also referred to as the Azimuthal Quantum Number, signified by the lower case L in the following relationship:

, where , the ellipsis implying the infinite set.

The greater the integer number the smaller the differences in quantum states and probably the more difficult it will be to tune the receiver.

[woodsmoke]

Hi GG.

Yes, I agree about Asimuthal Spin etc. a similar calculation is made with NMR, but, the comment was more about the terminology, such as "vortex" being rather reminiscent of ...maybe if that kind of terminology has to be used then there isn't much underneath in the first place.

Not to say that it is not correct, but the terminology leaves me, in a dubious azimuthal state .

woodsmoke

[GreyGeek]

Is there a medicine you can take for that "state"?

[MoonRise]

I'll just wait until they figure out subspace!

[SteveRiley]

the terminology leaves me, in a dubious azimuthal state

Is there a medicine you can take for that "state"?

A variety of pharmacological agents can help mitigate such concerns. For instance, alprazolam is a very effective mechanism for returning to normal after an extended session of, um, er, well, I suppose I actually mean coming down from a zenith now that I think about it. Wait, why am I mentioning this in a public forum?

[woodsmoke]

lol
woodinSUCHastatesmoke