Twisting The Light Away [Twisted Light]

New Scientist | June 12, 2004 | Stephen Battersby

[aimhigh]

My brain just exploded trying to understand the article.

[hereandnow]

I was thinking the same thing but polarization has more than two states. There are only two circular polarization states but there are two other polarizations vertical and horizontal polarizations. I think the writer of this article has a weak background in Quantum physics and is using terms out of context...

[forsnax5]

And I do know how to turn a flashlight on and off.

I thought that was an odd example of a way to send binary code -- how would you send two "offs" in a row?

;)

[roaddog727]

"This could be the humble beginning".

Bingo.

If Lucent, Juniper, and NORTEL can figure out how to make this kind of optical comm technology work over the existing fiber backbone, WOW!

Gig-e to your front door.

[BobS]

Vertical and horizontal polarizations are linear- E-plane and H-plane in uW transmission; it's the most common radar. Circular polarization, either right-circ. or left circ. rotates the beam at a 45 deg angle, so you have a 3 dB drop in power, but it works very well by penetrating rain, like an MC-130 Ku band pencil or shaped beam antenna.

The property talked about here discusses angular velocity of photons in a circumference inside a projection. I printed this out to read later in bed. My idea may change, but the discussion of a polarizer makes me think I am pretty close!

[spunkets]

These are circularly polarized EM waves. The article is goofy.

[sd-joe]

It seems to me that since the speed of light is fixed, it can not change the time to take the helical path as opposed to the straight path.

[Bear_in_RoseBear]

ping...

[BobS]

"These are circularly polarized EM waves. The article is goofy."

That is why I read these things before I sleep. During the next day sometime, I will remember it in the form of an idea. It hasn't failed in 20 years. I found a fix for countless problems that way, and all you have to do is lay around all night.

[spunkets]

" The property talked about here discusses angular velocity of photons in a circumference inside a projection."

Their analogy is to a charged particle moving in a circular motion. Photons don't orbit, 'cept maybe around a black hole of a certain size. Then the angular momentum carried by the generated circularly polarized wave is = rx(ExB)/c. More generally the angular momentum(l) is =Power/omega, where omega is the angular frequency of polarization. So the beam carriers l/unit area = ExB/omega/unit area. See this

[Alamo-Girl]

Thanks for the ping!

[BobS]

I know those things. But we are doing low-level measurements of power, if it is to be useful. Let's bring it to satellite levels illuminating the Earth. Those are typically -95 to -105 dBm on the surface before you preamp and demodulate them.

You need a noise figure measurement to characterice your system(s). You know, N = kTB where you filter out the microwave background radiation. And you deal with S/N ratio which can be corrupted by sunlight, so you get out in the middle of the night when the sun is on the opposite side from you to do this.

These people created a transmission form with an open end.

What is the reciever form?

[sweetliberty]

Thought y'all might find this interesting if you hadn't seen it before.

[itsamelman]

Then the angular momentum carried by the generated circularly polarized wave is = rx(ExB)/c. More generally the angular momentum(l) is =Power/omega, where omega is the angular frequency of polarization. So the beam carriers l/unit area = ExB/omega/unit area.

Uh, yeah, what you said.

[neuron2]

No graphics and no link to the original article. Shame! Back to Posting 101 for you.

[AndrewC]

Twisto World

[Talking_Mouse]

bump to read several times and try and understand

[philetus]

But, will it corkscrew the other direction in Australia?

[GOPJ]

Beam me up:

If you could stand on a wave crest and walk around the beam, after one complete circuit you would find yourself standing one wavelength away from where you started.

[<1/1,000,000th%]

Circular polarization.