Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Terahertz polarizer nears perfection: Research at Rice University leads to nanotube-based device for communication, security, sensing

A triple layer of carbon nanotube arrays on a sapphire base are the basis for a new type of terahertz polarizer invented at Rice University. The polarizer could lead to new security and communication devices, sensors and non-invasive medical imaging systems. (Credit: Lei Ren/Rice University)
A triple layer of carbon nanotube arrays on a sapphire base are the basis for a new type of terahertz polarizer invented at Rice University. The polarizer could lead to new security and communication devices, sensors and non-invasive medical imaging systems.

(Credit: Lei Ren/Rice University)

Abstract:
Researchers at Rice University are using carbon nanotubes as the critical component of a robust terahertz polarizer that could accelerate the development of new security and communication devices, sensors and non-invasive medical imaging systems as well as fundamental studies of low-dimensional condensed matter systems.

Terahertz polarizer nears perfection: Research at Rice University leads to nanotube-based device for communication, security, sensing

Houston, TX | Posted on January 30th, 2012

The polarizer developed by the Rice lab of Junichiro Kono, a professor of electrical and computer engineering and of physics and astronomy, is the most effective ever reported; it selectively allows 100 percent of a terahertz wave to pass or blocks 99.9 percent of it, depending on its polarization. The research was published in the online version of the American Chemical Society journal, Nano Letters.

The broadband polarizer handles waves from 0.5 to 2.2 terahertz, far surpassing the range of commercial polarizers that consist of fragile grids wrapped in gold or tungsten wires.

Kono said technologies that make use of the optical and electrical regions of the electromagnetic spectrum are mature and common, as in lasers and telescopes on one end and computers and microwaves on the other. But until recent years, the terahertz region in between was largely unexplored. "Over the past decade or two, people have been making impressive progress," he said, particularly in the development of such sources of radiation as the terahertz quantum cascade laser.

"We have pretty good terahertz emitters and detectors, but we need a way to manipulate light in this range," Kono said. "Our work is in this category, manipulating the polarization state -- the direction of the electric field -- of terahertz radiation."

Terahertz waves exist at the transition between infrared and microwaves and have unique qualities. They are not harmful and penetrate fabric, wood, plastic and even clouds, but not metal or water. In combination with spectroscopy, they can be used to read what Kono called "spectral fingerprints in the terahertz range"; he said they would, for instance, be useful in a security setting to identify the chemical signatures of specific explosives.

The work by Kono and lead author Lei Ren, who recently earned his doctorate at Rice, makes great use of the basic research into carbon nanotubes for which the university is famous. Co-authors Robert Hauge, a distinguished faculty fellow in chemistry, and his former graduate student Cary Pint developed a way to grow nanotube carpets and to transfer well-aligned arrays of nanotubes from a catalyst to any substrate they chose, limited only by the size of the growth platform.

While Hauge and Pint were developing their nanotube arrays, Kono and his team were thinking about terahertz. Four years ago, they came across a semiconducting material, indium antimonide, that would stop or pass terahertz waves, but only in a strong magnetic field and at very low temperatures.

At about the same time, Kono's lab began working with carbon nanotube arrays transferred onto a sapphire substrate by Pint and Hauge. Those aligned arrays -- think of a field of wheat run over by a steamroller -- turned out to be very effective at filtering terahertz waves, as Kono and his team reported in a 2009 paper.

"When the polarization of the terahertz wave was perpendicular to the nanotubes, there was absolutely no attenuation," Kono recalled. "But when the polarization was parallel to the nanotubes, the thickness was not enough to completely kill the transmission, which was still at 30-50 percent."

The answer was clear: Make the polarizer thicker. The current polarizer has three decks of aligned nanotubes on sapphire, enough to effectively absorb all of the incident terahertz radiation. "Our method is unique, and it's simple," he said.

Kono sees use for the device beyond spectroscopy by manipulating it with an electric field, but that will only become possible when all of the nanotubes in an array are of a semiconducting type. As they're made now, batches of nanotubes are a random mix of semiconductors and metallics; recent work by Erik Hároz, a graduate student in Kono's lab, detailed the reasons that nanotubes separated through ultracentrifugation have type-dependent colors. But finding a way to grow specific types of nanotubes is the focus of a great deal of research at Rice and elsewhere.

Co-authors are former Rice postdoctoral researcher Takashi Arikawa and research associate Iwao Kawayama and Professor Masayoshi Tonouchi of the Institute of Laser Engineering at Osaka University, Japan.

The Department of Energy, the National Science Foundation and the Robert A. Welch Foundation supported the research.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is known for its "unconventional wisdom." With 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is less than 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 4 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to www.rice.edu/nationalmedia/Rice.pdf.

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

Copyright © Rice University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Read the abstract at:

"Nanotubes Take Flight":

"Gecko's lessons transfer well":

"A see-through surprise":

"Carbon Nanotube Terahertz Polarizer":

"Nano parfait a treat for scientists":

"Scientists solve mystery of colorful armchair nanotubes":

Related News Press

News and information

Chemical interactions between silver nanoparticles and thiols: A comparison of mercaptohexanol again September 30th, 2014

A Heartbeat Away? Hybrid "Patch" Could Replace Transplants: TAU researcher harnesses gold nanoparticles to engineer novel biocompatible cardiac patch September 30th, 2014

Iranian Scientists Determine Grain Size, Minimize Time of Nanocomposite Synthesis September 29th, 2014

Nanoparticles Used to Improve Quality of Bone Cement September 29th, 2014

'Pixel' engineered electronics have growth potential: Rice, Oak Ridge, Vanderbilt, Penn scientists lead creation of atom-scale semiconducting composites September 29th, 2014

Imaging

Iranian Scientists Determine Grain Size, Minimize Time of Nanocomposite Synthesis September 29th, 2014

Oxford Instruments launches 3rd annual Indian nanotechnology seminars in Kolkata and Delhi - sharing expertise with Nanotechnology researchers in India September 25th, 2014

Physics

Brookhaven Lab's National Synchrotron Light Source II Approved to Start Routine Operations: Milestone marks transition to exciting new chapter September 23rd, 2014

Toward optical chips: A promising light source for optoelectronic chips can be tuned to different frequencies September 19th, 2014

Elusive Quantum Transformations Found Near Absolute Zero: Brookhaven Lab and Stony Brook University researchers measured the quantum fluctuations behind a novel magnetic material's ultra-cold ferromagnetic phase transition September 15th, 2014

Excitonic Dark States Shed Light on TMDC Atomic Layers: Berkeley Lab Discovery Holds Promise for Nanoelectronic and Photonic Applications September 11th, 2014

Nano-pea pod model widens electronics applications: A new theoretical model explains how a nanostructure, such as the nano-pea pod, can exhibit localised electrons September 4th, 2014

Law enforcement/Anti-Counterfeiting/Security/Loss prevention

Light detector to revolutionise night vision technology September 8th, 2014

Ultra-thin Detector Captures Unprecedented Range of Light September 7th, 2014

Nanotech Security Corp. to Acquire Fortress Optical Features Ltd., a Leading Producer of Banknote Security Features August 27th, 2014

Sensors

Graphene and Amaranthus Superparamagnets: Breakthrough nanoparticles discovery of Indian researcher September 23rd, 2014

IEEE International Electron Devices Meeting To Celebrate 60th Anniversary as The Leading Technical Conference for Advanced Semiconductor Devices September 18th, 2014

Biosensors Get a Boost from Graphene Partnership: $5 Million Investment Supports Dozens of Jobs and Development of 300mm Fabrication Process and Wafer Transfer Facility September 18th, 2014

The Pocket Project will develop a low-cost and accurate point-of-care test to diagnose Tuberculosis: ICN2 holds a follow-up meeting of the Project on September 18th - 19th September 18th, 2014

Discoveries

Chemical interactions between silver nanoparticles and thiols: A comparison of mercaptohexanol again September 30th, 2014

A Heartbeat Away? Hybrid "Patch" Could Replace Transplants: TAU researcher harnesses gold nanoparticles to engineer novel biocompatible cardiac patch September 30th, 2014

Iranian Scientists Determine Grain Size, Minimize Time of Nanocomposite Synthesis September 29th, 2014

Nanoparticles Used to Improve Quality of Bone Cement September 29th, 2014

Announcements

Chemical interactions between silver nanoparticles and thiols: A comparison of mercaptohexanol again September 30th, 2014

A Heartbeat Away? Hybrid "Patch" Could Replace Transplants: TAU researcher harnesses gold nanoparticles to engineer novel biocompatible cardiac patch September 30th, 2014

Iranian Scientists Determine Grain Size, Minimize Time of Nanocomposite Synthesis September 29th, 2014

Nanoparticles Used to Improve Quality of Bone Cement September 29th, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE