orbital angular momentum of light (OAM)

Hi Jamie

Somemany have written an article here:

It is incredible that no one has thought of that before.

Nov 1, 2012, physicsworld.com: Spooky action with twisted beams:

Quote: "... Using this technique, Zeilinger and co-workers found they could obtain differences in quantum number as high as 600 (in other words l = +300 on one photon and l = ?300 on the other). Lapkiewicz points out that there is, in theory, no upper limit to a photon's l value, which suggests that a photon ? a quantum object ? could acquire as much OAM as a macroscopic object, leading to what he calls a "tension between the quantum and classical worlds" ..."

Oct 19, 2012, physicsworld.com: Chip puts a twist on light:

Quote: "... Indeed, he says that they aim to produce devices that can emit different OAM values at the same time. This, he claims, could enhance telecommunication bandwidth, by increasing the number of channels available, and boost the power of quantum computers ? devices, still under development, that promise much faster data crunching by processing multiple quantum states simultaneously. "Currently, quantum computers rely on electron spin or photon spin, which only have two states, whereas OAM has many states," he explains ..."

25 June 2012, BBC News: 'Twisted light' carries 2.5 terabits of data per second: Quote: "... Recent work suggests that the trick could vastly boost the data-carrying capacity in wi-fi and optical fibres ... The idea is not to create light waves wiggling in different directions but rather with different amounts of twist, like screws with different numbers of threads ..."

University of Southern California (2013, June 27). Breakthrough in Internet bandwidth: New fiber optic technology could ease Internet congestion, video streaming. ScienceDaily: Quote: "... the technology centers on donut-shaped laser light beams called optical vortices, in which the light twists like a tornado as it moves along the beam path, rather than in a straight line ... Unlike in conventional fibers, OAM modes in these specially designed fibers can carry data streams across an optical fiber while remaining separate at the receiving end ..."

/Glenn

(answer to sci.electronics.design )

A radioamateur might have this question:

If a radio antenna radiate OAM-8 waves, how does the wavefront then look like?

-

I radio beacon might radiate in angles equal the OAM in one frequency only; e.g.:

0° = OAM-0 1° = OAM-1 ... 180° = OAM-180 ... 359° = OAM-359

or

0° = OAM-0 0.1° = OAM-1 1° = OAM-10 ... 180° = OAM-1800 ... 359.9° = OAM-3599

I do not know how the antenna system might look like - or if it even feasible.

With 2 or more OAM enabled radio beacons an approximate position on earth can be defined immediately.

-

If that is possible, a linear polarized wave can be used for longwave, shortwave time signal that will also pinpoint where you are on earth. It might be used for a new GPS, that can instantly make a approximate position in 3D around earth or other planets.

/Glenn

...

Silly me, the angle encoding should of cause use gray encoding:

Quote: "... To avoid the above problem, Gray encoding is used. This is a system of binary counting in which adjacent codes differ in only one position. For the three-contact example given above, the Gray-coded version would be as follows. ..."

/Glenn

It violates the second law of thermodynamics, of course, so it will almost certainly prove to be false.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 USA 
+1 845 480 2058 

hobbs at electrooptical dot net 
http://electrooptical.net

...

In what way?

Quote: "... Anton Zeilinger?s achievements have been most succinctly described in his citation for the Isaac Newton Medal of the Institute of Physics (UK): ?For his pioneering conceptual and experimental contributions to the foundations of quantum physics, which have become the cornerstone for the rapidly-evolving field of quantum information.? He is a pioneer in the field of quantum information and of the foundations of quantum mechanics. He realized many important quantum information protocols for the first time, including quantum teleportation, entanglement swapping, dense coding, entanglement-based quantum cryptography, one-way quantum computation and blind quantum computation. In addition, he made many important contributions to the conceptual and experimental foundations of quantum mechanics, particularly in the areas of quantum entanglement and macroscopic quantum mechanics. ..."

Science 2 November 2012: Vol. 338 no. 6107 pp. 640-643 DOI: 10.1126/science.1227193 Quantum Entanglement of High Angular Momenta Robert Fickler Radek Lapkiewicz William N. Plick Mario Krenn Christoph Schaeff Sven Ramelow Anton Zeilinger

Quote: "... In our experiment, polarization-entangled photon pairs (uncorrected average visibility 97.99 ± 0.03%) at 810 nm were created using a type II nonlinear crystal in a Sagnac-type configuration (26, 27). ... The highest value of OAM per single photon where strong correlations were still measurable was l = ±300 for both photons (Fig. 3C). ... When we transfer one photon to high OAM values and keep the other in its polarization state, the pair can be used to remotely measure an angular rotation with a precision that is increased by a factor l relative to the situation when only polarization-entangled photon pairs are used (Fig. 4) (22). ..."

/Glenn

The black body formula, abundantly confirmed by experiment, relies on an exhaustive enumeration of all the available states of the EM field, and they don't include the orbital angular momentum states.

The equipartition theorem requires that in thermodynamic equilibrium, all accessible states have the occupation number 1/(1+exp(h*nu/(k*T))). If there were really all those extra states, black bodies would radiate very much more intensely than they do.

So either (a) it's wrong, or (b) it's another Ultraviolet Catastrophe. My bet is on (a). The quantum optics people have been ludicrously wrong before now, e.g. the once firmly held claim that light from two different sources could never produce interference fringes.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 USA 
+1 845 480 2058 

hobbs at electrooptical dot net 
http://electrooptical.net

Wrong statistics--Bose-Einstein is 1/(1-exp(h*nu/(k*T))). Same argument.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 USA 
+1 845 480 2058 

hobbs at electrooptical dot net 
http://electrooptical.net

It appears that OAM is real, with lots or articles in such rags as Physical Review, but is detectable only in the nearfield. For one thing, the receiving antenna needs to intercept most of the beam, which has a centerline null.

This has also been implemented in the microwave band. Search for Professor Bo Thidé and collaborators:

The question is what OAM can be used for. It may work in fiber optics, and some of the literature on "vortex launch" talks of OAM, and some talks simply of avoiding the central defect of practical fiber (as I had described in a prior thread).

Joe Gwinn

Well, if it's all evanescent, big whoop. Everyone has known since Fourier that if you include evanescent modes, you have a complete basis set, so you can make anything you like. But it ain't too useful for communication, even quantum communication.

That wasn't the claim being made back at the beginning of all of this foofaraw.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 USA 
+1 845 480 2058 

hobbs at electrooptical dot net 
http://electrooptical.net

Hi,

I think OAM and the relativistic hall effect could give a physical description of E=mc^2 and physically describe the translation between energy and matter maybe. Maybe matter is light with significant OAM, and the relativistic hall effect asymmetry of its motion causes it to curve into a toroid shape or other shapes that can be self sustaining.

cheers, Jamie

Well, an Italian group managed to send microwave OAM signals a few hundred meters. This is enough for some things.

Yeah. Let's just say that a few important details became lost.

Joe Gwinn

On a sunny day (Sat, 03 Aug 2013 15:44:57 -0700) it happened Jamie M wrote in :

Snipped some, but I like Maxwell,

's_equations his equations are based on _fluid dynamics _. Now this is not my field, but when you mentioned that OAM I try visualizing with water as medium. Now I COULD imagine a rotating fan with a piezo beeper on it...

Sure, in the 'near by' (field LOL) the water would rotate a bit, and for sure a similar propeller would also start rotating. First thing that is clear here is that here will be a signal delay, sound in water moves at a fixed speed (sonar), and when moving in spirals the sound will be more delayed if spiral has more turns per unit of distance (cm duh).

So when moving away from such a [sonar] transmitter you will see timing issues.

Then I was thinking for sure if a professor starts thinking about this, then things will get more expensive, and some of his students will be assigned to write papers for their PhD thesis about this, and you can then staple (no that would be painful) so glue all those sheets of paper together to make a nice big roll of tissue paper. That will hurt trees and is not green at all, so here is also a political dilemma. Then I was thinking if you do the same and send the rotating water into a tube (fiber), maybe it will be seen to rotate over a longer distance (apart from friction etc). But can this be used to send more information>? Sure if it rotates faster or slower I am sure one of those papers will find a way, but to find the rotation in degrees per unit of length over a distance where it changes anyway, I think that would not be a very hope giving project.

From an aether POV it is interesting, and some of those tissues may be worth reading before use. Anyways I am no expert on that, I just do not like photon, kwantuum computahs are a hoax in my NSHO, and if there is any quantization it is on the level of the water molecules, not of the level of our ping pong balls (electrons connected to atoms) connected to poles as detectors. So, that was my 'Deep Thought' (not to be confused with that similar sounding movie) for this morning.

Standard ending of paper: We Think This Reseach Has Brought The Quantum Computer So Much Nearer With Additional Fundding And A Lifetime Of Research Nuclear Fusion Gravity Waves Quantum Computer OAM ??

Hi Jan,

Thanks for clearing that up!

cheers, Jamie

You mean m = 8? Look here:

and do the logical extrapolation.

Here's the general idea:

See figure A4 and table A2, about 2/3 of the way down the page. The sidel obes aren't shown but it looks to me like they'll be, er, messy.

In a Q&A forum I can't find right now I asked Thidé if a piezo element inserted in the gap in the dish could real-time modulate the value of m, an d he said "I don't know, we will have to try it".

Mark L. Fergerson

(answer to sci.electronics.design )

More about OAM - it is useful:

Aug 5, 2013, Rotational Doppler shift spotted in twisted light

"... The team fired two beams of light carrying orbital angular momentum at a rotating surface and showed that the resulting interference pattern in the reflected light is related to the surface's angular velocity. ... The frequency of the scattered beam with orbital angular momentum in the same direction as the surface is raised slightly (blue-shifted), while the frequency of the beam with angular momentum in the opposite direction is lowered (red-shifted) by the same amount (see figure). ... "I think it's quite unexpected and might be surprising that you have this Doppler effect even though there is nothing that is moving closer or farther from the detector," he says. "Of course, you can understand it with hindsight by reasoning about the effect, but without this work you would not expect it to occur." ..."

/Glenn

On a sunny day (Tue, 06 Aug 2013 07:25:31 +0200) it happened Glenn wrote in :

Strange I just predicted that in my post reply to Jamie (see timing issues). LOL

Really how seriously do we need to take all that publidhed crap these days that requires tons of funding.

;)

Cheers

Phil Hobbs

(Who is expecting to start a one-day-a-week gig in topological quantum computing. Fun.)

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

Hi Phil,

Cool, I read about it - sounds feasible kind of, "electron liquid" with quantized states appearing out of "no where", really interesting! Sounds like a new state of matter being created. I guess you are using graphene to avoid the low temperature requirements? (I was reading that graphene may not need the low temperatures for the effect to occur).

I have a feeling it is a good way to learn about electrons by studying this field! Pretty much unexplained though as I have read that the fine structure constant value is still an unsolved mystery.

cheers, Jamie

I was reading some more about the fine structure constant, and apparently it isn't actually a constant but will changed based on conditions, ie from wikipedia:

"While the fine-structure constant is known to approach 1/128 at interaction energies above 80 GeV"

The mystery of the fine structure constant has been that it's value is in a narrow range that allows for matter to exist, but this is looking at it backwards, since if the fine structure constant can change (as shown by the change in its value at 80GeV), then obviously it is changing based on the conditions, so it will take on a value that matches the conditions. So it's a variable.

cheers, Jamie