Featured Research

from universities, journals, and other organizations

See-through surprise: Lab makes solid material transparent to terahertz waves

Date:
December 9, 2009
Source:
Rice University
Summary:
Very often in science, the unexpected discovery turns out to be the most significant. Researchers weren't looking for a breakthrough in the transmission of terahertz signals, but there it was: a plasmonic material that would, with adjustments to its temperature and/or magnetic field, either stop a terahertz beam cold or let it pass completely.

Location of Terahertz waves in the electromagnetic spectrum.
Credit: Courtesy of Wikipedia

Very often in science, the unexpected discovery turns out to be the most significant. Rice University Professor Junichiro Kono and his team weren't looking for a breakthrough in the transmission of terahertz signals, but there it was: a plasmonic material that would, with adjustments to its temperature and/or magnetic field, either stop a terahertz beam cold or let it pass completely.

The finding by Kono, a professor in electrical and computer engineering and in physics and astronomy, former graduate student Xiangfeng Wang and their colleagues helps close a knowledge gap in the electromagnetic spectrum between the ranges that address electronic and photonic devices.

Their paper appears in the journal Nature Physics. Co-authors include Texas A&M theoretical physicist Alexey Belyanin, Los Alamos National Laboratory physicist Scott Crooker and Daniel Mittleman, a Rice professor in electrical and computer engineering.

Kono's team had been studying the conductivity of indium antimonide. "This is a classic material people started working on in the 1940s," he said. "It's a typical semiconductor, and if you dope it, it's highly conductive. But if you apply a magnetic field, it becomes an insulator, and that's what we planned to look at."

When Wang used terahertz spectroscopy to study the material, its unusual properties became apparent. "He started tuning various parameters -- the magnetic field, temperature and then the frequency -- and found that the terahertz transmission of the material changed drastically," Kono said. "It went from opaque to transparent."

They found that in a magnetic field, the doped indium antimonide, a solid-state plasma, transmitted circularly polarized waves that interfered with each other. This affected terahertz beams in much the same way polarized sunglasses interfere with visible light. To their surprise, at particular combinations of settings, the beams would pass right through.

"Terahertz is an exciting field right now," said Kono, a newly named fellow of the American Physical Society whose lab focuses on the physics and applications of semiconductor nanostructures and quantum devices. "This frequency range is considered to be the last frontier of the electromagnetic spectrum."

Kono said neither type of semiconductor device in common use today -- photonic and electronic -- works in the terahertz range. "Photonic devices work in the visible and near-infrared ranges and electronic devices work in the kilohertz, megahertz and gigahertz ranges. There's a clear gap where there's no mature solid-state technology. That's why a lot of people are working to fill it."

"I wouldn't say the terahertz region is unexplored, but it's less so," said Mittleman, who specializes in terahertz technologies and worked on the development of a terahertz version of Rice's famous single-pixel camera. "There are some open problems that people haven't thought about -- or have thought about, but haven't found good solutions for. The whole technology base is a lot less mature."

Kono said applications for terahertz technology include imaging, spectroscopy and communications, and having a device that can serve as a terahertz switch would be a step forward.

Still, there are hurdles to making the lab's discovery practical, one being the operating temperature. Wang worked with the indium antimonide at temperatures between 2 and 240 kelvins (approximately -456 to -27 degrees Fahrenheit).

"The temperature is certainly a concern," Mittleman said. "If it's going to have impact as a useful device for controlling terahertz beams, there is some work yet to do. I don't think that's impossible, but the route is not immediately clear.

"There's not a lot of shocking new physics here," he said, but the combination of techniques used to treat the indium antimonide made for interesting science. "People are going to think it's pretty cool.

"I think it's nice to find things like this, because it's a great example of an unexpected discovery that could turn out to be really useful."

The National Science Foundation and the Robert A. Welch Foundation supported the research.


Story Source:

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


Journal Reference:

  1. Wang et al. Interference-induced terahertz transparency in a semiconductor magneto-plasma. Nature Physics, 2009; DOI: 10.1038/nphys1480

Cite This Page:

Rice University. "See-through surprise: Lab makes solid material transparent to terahertz waves." ScienceDaily. ScienceDaily, 9 December 2009. <www.sciencedaily.com/releases/2009/12/091207123805.htm>.
Rice University. (2009, December 9). See-through surprise: Lab makes solid material transparent to terahertz waves. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2009/12/091207123805.htm
Rice University. "See-through surprise: Lab makes solid material transparent to terahertz waves." ScienceDaily. www.sciencedaily.com/releases/2009/12/091207123805.htm (accessed October 1, 2014).

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Japan Looks To Faster Future As Bullet Train Turns 50

Japan Looks To Faster Future As Bullet Train Turns 50

Newsy (Oct. 1, 2014) Japan's bullet train turns 50 Wednesday. Here's a look at how it's changed over half a century — and the changes it's inspired globally. Video provided by Newsy
Powered by NewsLook.com
US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
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