Featured Research

from universities, journals, and other organizations

Synthetic magnetism used to control light: Opens door to nanoscale applications that use light instead of electricity

Date:
October 31, 2012
Source:
Stanford School of Engineering
Summary:
Physics and engineering researchers have demonstrated a device that produces a synthetic magnetism to exert virtual force on photons similar to the effect of magnets on electrons. The advance could yield a new class of nanoscale applications that use light instead of electricity.

Promise of harnessing light. An advance could yield a new class of nanoscale applications that use light instead of electricity.
Credit: mrage / Fotolia

Stanford researchers in physics and engineering have demonstrated a device that produces a synthetic magnetism to exert virtual force on photons similar to the effect of magnets on electrons. The advance could yield a new class of nanoscale applications that use light instead of electricity.

Related Articles


Magnetically speaking, photons are the mavericks of the engineering world. Lacking electrical charge, they are free to run even in the most intense magnetic fields. But all that may soon change. In a paper published in Nature Photonics, an interdisciplinary team from Stanford University reports that it has created a device that tames the flow of photons with synthetic magnetism.

The process breaks a key law of physics known as the time-reversal symmetry of light and could yield an entirely new class of devices that use light instead of electricity for applications ranging from accelerators and microscopes to speedier on-chip communications.

"This is a fundamentally new way to manipulate light flow. It presents a richness of photon control not seen before," said Shanhui Fan, a professor of electrical engineering at Stanford and senior author of the study.

A Departure

The ability to use magnetic fields to redirect electrons is a founding principle of electronics, but a corollary for photons had not previously existed. When an electron approaches a magnetic field, it meets resistance and opts to follow the path of least effort, travelling in circular motion around the field. Similarly, this new device sends photons in a circular motion around the synthetic magnetic field.

The Stanford solution capitalizes on recent research into photonic crystals -- materials that can confine and release photons. To fashion their device, the team members created a grid of tiny cavities etched in silicon, forming the photonic crystal. By precisely applying electric current to the grid they can control -- or "harmonically tune," as the researchers say -- the photonic crystal to synthesize magnetism and exert virtual force upon photons. The researchers refer to the synthetic magnetism as an effective magnetic field.

The researchers reported that they were able to alter the radius of a photon's trajectory by varying the electrical current applied to the photonic crystal and by manipulating the speed of the photons as they enter the system. This dual mechanism provides a great degree of precision control over the photons' path, allowing the researchers to steer the light wherever they like.

Broken Laws

In fashioning their device, the team has broken what is known in physics as the time-reversal symmetry of light. Breaking time-reversal symmetry in essence introduces a charge on the photons that reacts to the effective magnetic field the way an electron would to a real magnetic field.

For engineers, it means that a photon travelling forward will have different properties than when it is traveling backward, the researchers said, and this yields promising technical possibilities. "The breaking of time-reversal symmetry is crucial as it opens up novel ways to control light. We can, for instance, completely prevent light from traveling backward to eliminate reflection," said Fan.

The new device, therefore, solves at least one major drawback of current photonic systems that use fiber optic cables. Photons tend to reverse course in such systems, causing a form of reflective noise known as backscatter.

"Despite their smooth appearance, glass fibers are, photonically speaking, quite rough. This causes a certain amount of backscatter, which degrades performance," said Kejie Fang, a doctoral candidate in the Department of Physics at Stanford and the first author of the study.

In essence, once a photon enters the new device it cannot go back. This quality, the researchers believe, will be key to future applications of the technology as it eliminates disorders such as signal loss common to fiber optics and other light-control mechanisms.

"Our system is a clear direction toward demonstrating on-chip applications of a new type of light-based communication device that solves a number of existing challenges," said Zongfu Yu, a post-doctoral researcher in Shanhui Fan's lab and co-author of the paper. "We're excited to see where it leads."


Story Source:

The above story is based on materials provided by Stanford School of Engineering. The original article was written by Andrew Myers. Note: Materials may be edited for content and length.


Journal Reference:

  1. Kejie Fang, Zongfu Yu, Shanhui Fan. Realizing effective magnetic field for photons by controlling the phase of dynamic modulation. Nature Photonics, 2012; DOI: 10.1038/nphoton.2012.236

Cite This Page:

Stanford School of Engineering. "Synthetic magnetism used to control light: Opens door to nanoscale applications that use light instead of electricity." ScienceDaily. ScienceDaily, 31 October 2012. <www.sciencedaily.com/releases/2012/10/121031151609.htm>.
Stanford School of Engineering. (2012, October 31). Synthetic magnetism used to control light: Opens door to nanoscale applications that use light instead of electricity. ScienceDaily. Retrieved January 25, 2015 from www.sciencedaily.com/releases/2012/10/121031151609.htm
Stanford School of Engineering. "Synthetic magnetism used to control light: Opens door to nanoscale applications that use light instead of electricity." ScienceDaily. www.sciencedaily.com/releases/2012/10/121031151609.htm (accessed January 25, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Sunday, January 25, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NTSB: Missing Planes' Black Boxes Should Transmit Wirelessly

NTSB: Missing Planes' Black Boxes Should Transmit Wirelessly

Newsy (Jan. 23, 2015) In light of high-profile plane disappearances in the past year, the NTSB has called for changes to make finding missing aircraft easier. Video provided by Newsy
Powered by NewsLook.com
Iconic Metal Toy Meccano Goes Robotic

Iconic Metal Toy Meccano Goes Robotic

Reuters - Innovations Video Online (Jan. 22, 2015) Classic children&apos;s toy Meccano has gone digital, releasing a programmable kit robot that can be controlled by voice recognition. The toymakers say Meccanoid G15 KS is easy to use and is compatible with existing Meccano pieces. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
The VueXL From VX1 Immersive Smartphone Headset!

The VueXL From VX1 Immersive Smartphone Headset!

Rumble (Jan. 22, 2015) The VueXL from VX1 is a product that you install your smartphone in and with the magic of magnification lenses, enlarges your smartphones screen so that it&apos;s like looking at a big screen TV. Check it out! Video provided by Rumble
Powered by NewsLook.com
Analysis: NTSB Wants Better Black Boxes

Analysis: NTSB Wants Better Black Boxes

AP (Jan. 22, 2015) NTSB investigators recommended Thursday that long-distance passenger planes carry improved technology to allow them to be found more easily in a crash, as well as include enhanced cockpit recording technology. (Jan. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins