Navigation Links
Research at Rice University leads to nanotube-based device for communication, security, sensing
Date:1/31/2012

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.

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 Hroz, 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.


'/>"/>

Contact: David Ruth
david@rice.edu
713-348-6327
Rice University
Source:Eurekalert

Related biology technology :

1. Maryland Stem Cell Research Commission Announces New Program for Pre-Clinical and Clinical Research Grants
2. New Software from SRI Speeds Development of Genome-Scale Models for Drug and Fuel Research
3. Chinese Scientists Zhen-Yi Wang and Zhu Chen Awarded 7th Annual Szent-Gyorgyi Prize for Progress in Cancer Research
4. Gene therapy research from Penn Vet & Scheie Eye Inst. cures retinitis pigmentosa in dogs
5. Van Andel Research Institute Study Provides New Details of Fundamental Cellular Process
6. PharmaVentures Helps Secure Investor for Former MSD Research Site
7. Niels Bohr Institute gets top researcher from Harvard
8. Hemodialysis Machine Industry 2012 Global & China Market Research Report - ReportsnReports
9. The Lancet Makes Research More Accessible for Healthcare Professionals With New App for iPad
10. Fifth Cycle of Probiotics & Microbiota Research Grant Announced
11. Navy researchers investigate small-scale autonomous planetary explorers
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:12/8/2016)... AskLinkerReports.com has published a report on ... Industry 2016 Market Research Report. From a basic outline of ... are all covered in the report. This report projects investment ... of the Amyloglucosidase industry. ... , , Complete ...
(Date:12/8/2016)... Portland, Oregon (PRWEB) , ... December 08, 2016 ... ... modules and the FrontPanel SDK that provide essential device-to-computer interconnect using USB or ... do not require FrontPanel support. The FOMD-ACV-A4 is a small, thin, SODIMM-style module ...
(Date:12/8/2016)... Maryland (PRWEB) , ... December ... ... announces the commercial launch of flexible packaging for their exceptionally efficient ... disposable bag system extends RoosterBio’s portfolio of bioprocess media products engineered to ...
(Date:12/8/2016)... , Dec. 8, 2016  HedgePath Pharmaceuticals, Inc. ... discovers, develops and plans to commercialize innovative therapeutics ... of common stock were approved for trading on ... trading on the OTCQX, effective today, under the ... the OTCQX market, companies must meet high financial ...
Breaking Biology Technology:
(Date:12/2/2016)... 1, 2016   SoftServe , a global ... , an electrocardiogram (ECG) biosensor analysis system for ... IoT asset. The smart system ensures device-to-device communication ... wheel and mobile devices to easily ,recognize, and ... As vehicle technology advances, so too must the ...
(Date:11/30/2016)... -- higi SH llc (higi) announced today the launch ... industry thought-leaders and celebrity influencers looking to encourage, ... steps to live healthier, more active lives. ... built the largest self-screening health station network in ... have conducted over 185 million biometric screenings.  The ...
(Date:11/29/2016)... , Nov. 29, 2016   Neurotechnology ... and object recognition technologies, today released FingerCell ... fingerprint recognition solutions that run on low-power, ... template using less than 128KB of memory, ... devices that have limited on-board resources, such ...
Breaking Biology News(10 mins):