Featured Research

from universities, journals, and other organizations

Solid-state Metamaterial Device Tames Terahertz Frequency

Date:
March 3, 2009
Source:
Boston College
Summary:
Terahertz radiation, a fleeting phase of the electromagnetic spectrum, has proved difficult to manipulate with great precision. Scientists report engineering a solid-state metamaterial device capable of controlling a terahertz beam 30 times faster than a conventional optical device. The device could prove critical to new applications employing the terahertz frequency.

An engineered metamaterial proved it can function as a state-of-the-art device in the complex terahertz range of the electromagnetic spectrum, setting a standard of performance for modulating tiny waves of radiation, according to a team of researchers from Boston College, the Los Alamos and Sandia national laboratories, and Boston University.

An electrical current applied to the metamaterial – a hybrid structure of metallic split-ring resonators – controlled the phase of a terahertz (THz) beam 30 times faster and with far greater precision than a conventional optical device, the researchers report in the current online edition of the journal Nature Photonics.

The discovery marks a milestone in the use of metamaterials and terahertz radiation, a safe, non-ionizing frequency that is the subject of a growing body of research and viewed as a promising component in applications that include advanced security screening systems and imaging technologies.

"This is a true metamaterial device," Boston College Asst. Prof. of Physics Willie J. Padilla, one of the co-authors of the paper, said. "This highlights the fact that you can make solid state devices at terahertz frequencies with metamaterials."

Constructed on the micron-scale, metamaterials are composites that use unique metallic contours in order to produce responses to light waves, giving each metamaterial its own unique properties beyond the elements of the actual materials in use. Within the past decade, researchers have sought ways to significantly expand the range of material responses to waves of electromagnetic radiation – classified by increasing frequency as radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. These metamaterials have demonstrated numerous novel effects that defy accepted electromagnetic principles.

Previously, in systems known as THz time domain spectrometers, the flow of terahertz radiation has been modulated indirectly by optical choppers, mechanical devices that either blocked a laser or allowed it to pass through. This "all or nothing" approach – similar to opening and closing the shutter of a camera – limits the speed with which one can manipulate terahertz waves since the chopper's mechanical components are too slow, Padilla says.

The metamaterial devised by the research team electronically controlled the flow of terahertz radiation over roughly 70 percent of the frequency band – not simply at the points of maximum or minimum frequency.

"We can apply an electronic signal to this device, thus making it opaque to stop terahertz, or transparent to allow terahertz through," Padilla said. "Eventually, you can turn it on and off very quickly – and that allows you to modulate the beam at a very specific frequency."

Because the metamaterial device is solid-state, eliminating moving parts, it is 30 times faster than the optical chopper, according to the report, co-authored by Hou-Tong Chen, Abul K. Azad and Antoinette J. Taylor of Los Alamos National Laboratory, Michael J. Cich of Sandia National Laboratories and Richard D. Averitt of Boston University

"The advantage of the metamaterial is you are doing it electronically," Padilla said. "If you want to build a device, the advantage of this is that it is all solid-state and voltage controlled. You have no moving parts. Therefore, you can modulate at very high speeds."

These kinds of controls have been developed for microwave and optical frequencies and led to a number of key breakthroughs, the researchers note. But the technologies have not extended to the terahertz frequency.

Padilla said a solid-state metamaterial device is a critical step toward improved terahertz devices, such as cameras or scanners.

"What we've shown with this metamaterial is that it is now improved to the point where it could be used as a device," Padilla said. "It could be the device you could use to build a terahertz system."

The research is supported by the Laboratory Directed Research and Development program at Los Alamos National Laboratory.


Story Source:

The above story is based on materials provided by Boston College. Note: Materials may be edited for content and length.


Cite This Page:

Boston College. "Solid-state Metamaterial Device Tames Terahertz Frequency." ScienceDaily. ScienceDaily, 3 March 2009. <www.sciencedaily.com/releases/2009/02/090224133152.htm>.
Boston College. (2009, March 3). Solid-state Metamaterial Device Tames Terahertz Frequency. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2009/02/090224133152.htm
Boston College. "Solid-state Metamaterial Device Tames Terahertz Frequency." ScienceDaily. www.sciencedaily.com/releases/2009/02/090224133152.htm (accessed July 31, 2014).

Share This




More Matter & Energy News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
Powered by NewsLook.com
U.K. To Allow Driverless Cars On Public Roads

U.K. To Allow Driverless Cars On Public Roads

Newsy (July 30, 2014) Driverless cars could soon become a staple on U.K. city streets, as they're set to be introduced to a few cities in 2015. 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