Featured Research

from universities, journals, and other organizations

Physicists find right (and left) solution for on-chip optics: Nanoscale router converts and directs optical signals efficiently

Date:
April 22, 2013
Source:
Harvard School of Engineering and Applied Sciences
Summary:
Scientists have created a new type of nanoscale device that converts an optical signal into waves that travel along a metal surface. Significantly, the device can recognize specific kinds of polarized light and accordingly send the signal in one direction or another.

Two different devices based on the herringbone pattern were presented in the Science paper: a rectangular array and a ring-shaped array (both interpreted in this illustration). Circularly polarized light with waves that wind in opposite directions gets split by both devices, with its waves routed in opposite directions. For a ring-shaped coupler, this means that plasmons are channeled either toward or away from the center of the structure. Intensity at the center of the ring can therefore be switched on and off by manipulating the polarization of the incoming light.
Credit: Image courtesy of Jiao Lin and Samuel Twist

A Harvard-led team of researchers has created a new type of nanoscale device that converts an optical signal into waves that travel along a metal surface. Significantly, the device can recognize specific kinds of polarized light and accordingly send the signal in one direction or another.

The findings, published in the April 19 issue of Science, offer a new way to precisely manipulate light at the subwavelength scale without damaging a signal that could carry data. This opens the door to a new generation of on-chip optical interconnects that can efficiently funnel information from optical to electronic devices.

"If you want to send a data signal around on a tiny chip with lots of components, then you need to be able to precisely control where it's going," says co-lead author Balthasar Mόller, a graduate student at the Harvard School of Engineering and Applied Sciences (SEAS). "If you don't control it well, information will be lost. Directivity is such an important factor."

The coupler transforms incoming light into a wave called a surface plasmon polariton, a surface ripple in the sea of electrons that exists inside metals.

In the past, it has been possible to control the direction of these waves by changing the angle at which light strikes the surface of the coupler, but, as Mόller puts it, "This was a major pain. Optical circuits are very difficult to align, so readjusting the angles for the sake of routing the signal was impractical."

With the new coupler, the light simply needs to come in perpendicularly, and the device does the rest. Acting like a traffic controller, it reads the polarization of the incoming light wave -- which might be linear, left-hand circular, or right-hand circular -- and routes it accordingly. The device can even split apart a light beam and send parts of it in different directions, allowing for information transmission on multiple channels.

The coupler consists of a thin sheet of gold, peppered with tiny perforations. But the precise pattern of these slits, arranged rather like herringbones, is where the genius lies.

"The go-to solution until now has been a series of parallel grooves known as a grating, which does the trick but loses a large portion of the signal in the process," says principal investigator Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at Harvard SEAS. "Now perhaps the go-to solution will be our structure. It makes it possible to control the direction of signals in a very simple and elegant way."

Because the new structure is so small -- each repeating unit of the pattern is smaller than the wavelength of visible light -- the researchers believe it should be easy to incorporate the design into novel technologies, such as flat optics.

Yet Capasso speaks most animatedly about the possibilities for incorporating the new coupler into future high-speed information networks that may combine nanoscale electronics (which currently exist) with optical and plasmonic elements on a single microchip.

"This has generated great excitement in the field," Capasso says.

Mόller and Capasso were joined on this work by co-lead author Jiao Lin, a former SEAS postdoctoral fellow who is now at the Singapore Institute of Manufacturing Technology; and coauthors Qian Wang and Guanghui Yuan, of Nanyang Technological University, Singapore; Nicholas Antoniou, Principal FIB Engineer at the Harvard Center for Nanoscale Systems; and Xiao-Cong Yuan, a professor at the Institute of Modern Optics at Nankai University in China.

The research was supported by the U.S. Air Force Office of Scientific Research, the Agency for Science, Technology, and Research (A*STAR) in Singapore, the National Natural Science Foundation of China, the Ministry of Science and Technology of China, and the National Research Foundation of Singapore. Part of the work was performed at the Harvard Center for Nanoscale Systems, which is a member of the National Nanotechnology Infrastructure Network, supported by the U.S. National Science Foundation.


Story Source:

The above story is based on materials provided by Harvard School of Engineering and Applied Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Lin, J. P. B. Mueller, Q. Wang, G. Yuan, N. Antoniou, X.-C. Yuan, F. Capasso. Polarization-Controlled Tunable Directional Coupling of Surface Plasmon Polaritons. Science, 2013; 340 (6130): 331 DOI: 10.1126/science.1233746

Cite This Page:

Harvard School of Engineering and Applied Sciences. "Physicists find right (and left) solution for on-chip optics: Nanoscale router converts and directs optical signals efficiently." ScienceDaily. ScienceDaily, 22 April 2013. <www.sciencedaily.com/releases/2013/04/130422143313.htm>.
Harvard School of Engineering and Applied Sciences. (2013, April 22). Physicists find right (and left) solution for on-chip optics: Nanoscale router converts and directs optical signals efficiently. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2013/04/130422143313.htm
Harvard School of Engineering and Applied Sciences. "Physicists find right (and left) solution for on-chip optics: Nanoscale router converts and directs optical signals efficiently." ScienceDaily. www.sciencedaily.com/releases/2013/04/130422143313.htm (accessed September 20, 2014).

Share This



More Matter & Energy News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) — The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) — Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) — Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) — Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
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:
from the past week

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