Defying physics, engineers prove a magnetic field for light

September 11, 2014 by Anne Ju, Cornell University
Defying physics, engineers prove a magnetic field for light
An illustration of the nonreciprocity of the dynamics of light propagating in the forward (a) and the backward (b) direction. Credit: Nature Photonics

In electronics, changing the path of electrons and manipulating how they flow is as easy as applying a magnetic field.

Not so for . "We don't have such a thing for light," said Michal Lipson, professor of electrical and computer engineering. "For the majority of materials, there is no such thing as something I can turn on, and apply this magic field to change the path of light."

Until now. Lipson, a leader in the emerging field of – sending light through waveguides instead of currents through wires – and colleagues have shown that an equivalent field for light does exist. Experiments led by graduate student Lawrence Tzuang, in collaboration with Paulo Nussenzveig of University of Sao Paulo and Kejie Fang and Shanhui Fan from Stanford University, are described in a recent issue of Nature Photonics.

This effective has to do with the light's phase, which is a measure of a particular point in a light wave's cycle, quantified as an angle in degrees.

The researchers demonstrated the existence of this field with an experimental interferometer, a micron-scale device with two modulators that send back and forth between them.

When a light wave travels under normal conditions, its phase is proportional to how far it traveled, but it is unaffected by what path it has taken. Just like a magnetic field causes a current to switch direction, the researchers showed that by modulating the light with their device, they could make the phase of the light change not only as a function of distance traveled, but also by the shape of its path.

An array of such modulators would be powerful enough to create a field for light that is equivalent to the magnetic field for electrons; phases of light could be controlled arbitrarily by each of the modulators. This means that the phase of transmitted light could depend on the path it has taken from point A to point B, Lipson explained.

"That puts us very close to what electrons do in a magnetic field; they experience exactly that in a magnetic field: The phase accumulated in their trajectory depends on the exact path they have taken," Lipson added.

Lipson and colleagues dream of controlling light at the smallest scales and in the most fundamental ways, using optics instead of wires on circuits to revolutionize electronics. Reaching this goal depends on the ability to propagate and control light in nontraditional ways, of which the Nature Photonics work is an example.

"One could in principle make fabrics of similar devices that would imprint phase and control the path of light in ways you couldn't conceive before," Lipson said.

Explore further: Researchers demonstrate infrared light modulation with graphene

More information: "Non-reciprocal phase shift induced by an effective magnetic flux for light." Lawrence D. Tzuang, Kejie Fang, Paulo Nussenzveig, Shanhui Fan & Michal Lipson Nature Photonics 8, 701–705 (2014) DOI: 10.1038/nphoton.2014.177. Received 03 April 2014 Accepted 02 July 2014 Published online 03 August 2014

Related Stories

Manipulating magnetic forces with light

August 6, 2014

The magnetic forces in magnetic materials like iron can be rapidly manipulated with light. Rubicon Researcher Johan Mentink, together with Martin Eckstein from the University of Hamburg CFEL/MPSD, has theoretically demonstrated ...

Multimode waveguides bring light around corners

December 14, 2012

(Phys.org)—Light has become one of our most powerful servants, carrying information ranging from a chat room "LOL" to an entire digitized movie through hundreds of miles of fiber optics in seconds. But like many servants, ...

Recommended for you

Bringing a hidden superconducting state to light

February 16, 2018

A team of scientists has detected a hidden state of electronic order in a layered material containing lanthanum, barium, copper, and oxygen (LBCO). When cooled to a certain temperature and with certain concentrations of barium, ...

18 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

DocEigen
5 / 5 (3) Sep 11, 2014
I did this is in the 70's using an external gas cavity on a HeNe laser.
Jixo
Sep 11, 2014
This comment has been removed by a moderator.
marcush
1 / 5 (3) Sep 11, 2014
.
russell_russell
4.3 / 5 (6) Sep 11, 2014
You can make the phase space of light behave like a magnetic field.
Are you allow to re-label the phase space of light a magnetic field solely based on behavior that mimics the magnetic field effect electrons undergo or exhibit?
Is the title misleading?
Ans:
Yes.
Is the title confusing?
Yes.
Are modulators really effective fields?
katesisco
not rated yet Sep 11, 2014
I have noticed this type of 'relabeling as new' science often in these science sites. My assumption is that lacking the next new thing, we have to keep the air stirred by relabeling, hoping the next big thing will actually occur.
I am thinking that each solar magnetic reversal cycle drains the magnetic field a bit more, even tho now we have very little. This results in an increase of gravity. This demands more energy to leave our gravity well explaining why the recent launches need greater expenditure of energy engines. The result of being in orbit around a dying magnetar, our Sol.
julianpenrod
2 / 5 (4) Sep 11, 2014
Maxwell's model of light is as a pair of mutually generating electrostatic and magnetic waves. The oscillating electrostatic field gives rise to the magnetic field, but the magnetic field oscillating produces the oscillating electrostatic field. It seems unlikely that there could not already have been a magnetic field methodology for directing light waves. In an early text on physics, Isaac Asimov, in fact, a picture of a super fine wire mesh with light going through it was magnified to show extreme visual distortion, due to the interaction of the magnetic field of light with the metal of the mesh. This sounds very much like "scientists" taking advantage of devotees' general lack of familiarity with anything except what the "scientists" tell them.
Whydening Gyre
5 / 5 (2) Sep 11, 2014
You can make the phase space of light behave like a magnetic field.
Are you allow to re-label the phase space of light a magnetic field solely based on behavior that mimics the magnetic field effect electrons undergo or exhibit?
Is the title misleading?
Ans:
Yes.
Is the title confusing?
Yes.
Are modulators really effective fields?

No. they are effective "field modulators" and no, this is not magnetism, per se...
Whydening Gyre
5 / 5 (4) Sep 11, 2014
I have noticed this type of 'relabeling as new' science often in these science sites. My assumption is that lacking the next new thing, we have to keep the air stirred by relabeling, hoping the next big thing will actually occur.

Agree with this statement. That is the nature of "periodical" journalism. It's not a "science" site, it's a "relay to the less informed masses" site.
I am thinking that each solar magnetic reversal cycle drains the magnetic field a bit more, even tho now we have very little. This results in an increase of gravity. This demands more energy to leave our gravity well explaining why the recent launches need greater expenditure of energy engines. The result of being in orbit around a dying magnetar, our Sol.

Not so sure about this statement, tho... I always thought they needed bigger rockets to handle bigger payloads.
I sense a "crock" factor...

MrVibrating
5 / 5 (2) Sep 11, 2014
You can make the phase space of light behave like a magnetic field.
Are you allow to re-label the phase space of light a magnetic field solely based on behavior that mimics the magnetic field effect electrons undergo or exhibit?
Is the title misleading?
Ans:
Yes.
Is the title confusing?
Yes.
Are modulators really effective fields?

No. they are effective "field modulators" and no, this is not magnetism, per se...

Point is, the magnetic feild is an objective thing, whereas geometric order is abstract. It's apples to oranges - a poor analogy implying something more extravagent than what's actually demonstrated..

Ie.:
"The researchers demonstrated the existence of this field"


"field"? Really?
Urgelt
5 / 5 (4) Sep 11, 2014
MIsleading lede, bad use of terms... not good.

Y'know, science journalism is still journalism, and there are some basic rules for it. One of them is 'check facts.' You do not check facts with the submitter of a news release; you get independent experts to weigh in.
homeunt
not rated yet Sep 11, 2014
What happened to lights being "ElectroMAGNETIC waves"? I think whoever wrote this journal never reviewed the Maxwell's equation
Aligo
Sep 11, 2014
This comment has been removed by a moderator.
Aligo
Sep 11, 2014
This comment has been removed by a moderator.
christophe_galland1
5 / 5 (2) Sep 12, 2014
The misleading and confusing title is no pride for Cornell University communication team. Does it even make sense for researchers to "defy physics"?

Fortunately the quotations from M. Lipson look accurate. Congratulation to her group for their work!

BTW, you can get the same non-reciprocal effect with standard optical fiber components:

"Experimental demonstration of broadband Lorentz non-reciprocity in an integrable photonic architecture based on Mach-Zehnder modulators"
Optics Express, Vol. 22, Issue 14, pp. 17409-17422 (2014)
http://dx.doi.org...2.017409
Whydening Gyre
not rated yet Sep 12, 2014
Marcush,
While it's a bit nonsensical at first look, I totally agree with that statement...
Da Schneib
not rated yet Sep 12, 2014
Lousy explanation of the effect. It's not any sort of magnetism. Sorry, this article gets a bad rating from me.
swordsman
not rated yet Sep 12, 2014
Failure to comprehend the transverse nature of light. Back to Heaviside.
PhotonX
not rated yet Sep 13, 2014
I am thinking that each solar magnetic reversal cycle drains the magnetic field a bit more, even tho now we have very little. This results in an increase of gravity. This demands more energy to leave our gravity well explaining why the recent launches need greater expenditure of energy engines. The result of being in orbit around a dying magnetar, our Sol.
So, just to be clear, you are asserting that gravity is not only increasing, but increasing at such a rate as to be noticeable over the last half century? And that the Sun (Sol if you're speaking Spanish or Latin, maybe) is a magnetar, a neutron star? Is that really what you're saying? If it is, what credible source can you cite to support either one of these outlandish claims?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.