Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Tiny laser sensor heightens bomb detection sensitivity

The plasmon laser sensor consists of a thin slab of semiconductor separated from the metal surface by a dielectric gap layer. Surface defects on the semiconductor interact with molecules of the explosive DNT.  Image by Ren-Min Ma and Sadao Ota
The plasmon laser sensor consists of a thin slab of semiconductor separated from the metal surface by a dielectric gap layer. Surface defects on the semiconductor interact with molecules of the explosive DNT.

Image by Ren-Min Ma and Sadao Ota

Abstract:
New technology under development at the University of California, Berkeley, could soon give bomb-sniffing dogs some serious competition.

Tiny laser sensor heightens bomb detection sensitivity

Berkeley, CA | Posted on July 19th, 2014

A team of researchers led by Xiang Zhang, UC Berkeley professor of mechanical engineering, has found a way to dramatically increase the sensitivity of a light-based plasmon sensor to detect incredibly minute concentrations of explosives. They noted that it could potentially be used to sniff out a hard-to-detect explosive popular among terrorists.

Their findings are to be published Sunday, July 20, in the advanced online publication of the journal Nature Nanotechnology.

They put the sensor to the test with various explosives - 2,4-dinitrotoluene (DNT), ammonium nitrate and nitrobenzene - and found that the device successfully detected the airborne chemicals at concentrations of 0.67 parts per billion, 0.4 parts per billion and 7.2 parts per million, respectively. One part per billion would be akin to a blade of grass on a football field.

The researchers noted that this is much more sensitive than the published results to date for other optical sensors.

"Optical explosive sensors are very sensitive and compact," said Zhang, who is also director of the Materials Science Division at the Lawrence Berkeley National Laboratory and director of the National Science Foundation Nanoscale Science and Engineering Center at UC Berkeley. "The ability to magnify such a small trace of an explosive to create a detectable signal is a major development in plasmon sensor technology, which is one of the most powerful tools we have today."

The new sensor could have many advantages over current bomb-screening methods.

"Bomb-sniffing dogs are expensive to train and they can become tired," said study co-lead author Ren-Min Ma, an assistant professor of physics at Peking University who did this work when he was a postdoctoral researcher in Zhang's lab. "The other thing we see at airports is the use of swabs to check for explosive residue, but those have relatively low-sensitivity and require physical contact. Our technology could lead to a bomb-detecting chip for a handheld device that can detect the tiny-trace vapor in the air of the explosive's small molecules."

The sensor could also be developed into an alarm for unexploded land mines that are otherwise difficult to detect, the researchers said. According to the United Nations, landmines kill 15,000 to 20,000 people every year. Most of the victims are children, women and the elderly.

Unstable and hungry for electrons

The nanoscale plasmon sensor used in the lab experiments is much smaller than other explosive detectors on the market. It consists of a layer of cadmium sulfide, a semiconductor, laid on top of a sheet of silver with a layer of magnesium fluoride in the middle.

In designing the device, the researchers took advantage of the chemical makeup of many explosives, particularly nitro-compounds such as DNT and its more well-known relative, TNT. Not only do the unstable nitro groups make the chemicals more explosive, they are also characteristically electron deficient, the researchers said. This quality increases the interaction of the molecules with natural surface defects on the semiconductor. The device works by detecting the increased intensity in the light signal that occurs as a result of this interaction.

Potential use to sense hard-to-detect explosive

"We think that higher electron deficiency of explosives leads to a stronger interaction with the semiconductor sensor," said study co-lead author Sadao Ota, a former Ph.D. student in Zhang's lab who is now an assistant professor of chemistry at the University of Tokyo.

Because of this, the researchers are hopeful that their plasmon laser sensor could detect pentaerythritol tetranitrate, or PETN, an explosive compound considered a favorite of terrorists. Small amounts of it pack a powerful punch, and because it is plastic, it escapes x-ray machines when not connected to detonators. It is the explosive found in Richard Reid's shoe bomb in 2001 and Umar Farouk Abdulmtallab's underwear bomb in 2009.

U.S. Attorney General Eric Holder Jr. was recently quoted in news reports as having "extreme, extreme concern" about Yemeni bomb makers joining forces with Syrian militants to develop these hard-to-detect bombs, which can be hidden in cell phones and mobile devices.

"PETN has more nitro functional groups and is more electron deficient than the DNT we detected in our experiments, so the sensitivity of our device should be even higher than with DNT," said Ma.

Latest generation of plasmon sensors

The sensor represents the latest milestone in surface plasmon sensor technology, which is now used in the medical field to detect biomarkers in the early stages of disease.

The ability to increase the sensitivity of optical sensors had traditionally been restricted by the diffraction limit, a limitation in fundamental physics that forces a tradeoff between how long and how small light can be trapped. By coupling electromagnetic waves with surface plasmons, the oscillating electrons found at the surface of metals, researchers were able to squeeze light into nanosized spaces, but sustaining the confined energy was challenging because light tends to dissipate at a metal's surface.

The new device builds upon earlier work in plasmon lasers by Zhang's lab that compensated for this light leakage by using reflectors to bounce the surface plasmons back and forth inside the sensor - similar to the way sound waves are reflected across the room in a whispering gallery - and using the optical gain from the semiconductor to amplify the light energy.

Zhang said the amplified sensor creates a much stronger signal than the passive plasmon sensors currently available, which work by detecting shifts in the wavelength of light. "The difference in intensity is similar to going from a light bulb for a table lamp to a laser pointer," he said. "We create a sharper signal which makes it easier to detect even smaller changes for tiny traces of explosives in the air."

The researchers noted that the sensor could have applications beyond chemical and explosive detection, such as use in biomolecular research.

The U.S. Air Force Office of Scientific Research Multi-University Research Initiative program helped support this work.

####

For more information, please click here

Contacts:
Sarah Yang
Media Relations

(510) 643-7741

Xiang Zhang

(510) 225-8559

Ren-Min Ma

(510) 984-3586
(Email first to schedule interview)

Sadao Ota

(510) 984-4551
(Email first to schedule interview)

Copyright © University of California Berkeley

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

Engineers take plasmon lasers out of deep freeze (UC Berkeley press release):

World's smallest semiconductor laser heralds new era in optical science (UC Berkeley press release):

Related News Press

News and information

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Thermal modification of wood and a complex study of its properties by magnetic resonance May 26th, 2016

Sensors

The next generation of carbon monoxide nanosensors May 26th, 2016

Dartmouth team creates new method to control quantum systems May 24th, 2016

Electronic device detects molecules linked to cancer, Alzheimer's and Parkinson's: An inexpensive portable biosensor has been developed by researchers at Brazil's National Nanotechnology Laboratory with FAPESP's support May 20th, 2016

Making organs transparent to improve nanomedicine (video) May 13th, 2016

Discoveries

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

PETA science group publishes a review on pulmonary effects of nanomaterials: Archives of Toxicology publishes a review of scientific studies on fibrotic potential of nanomaterials May 26th, 2016

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Announcements

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Thermal modification of wood and a complex study of its properties by magnetic resonance May 26th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Homeland Security

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

Nanoporous material's strange "breathing" behavior April 7th, 2016

Sniffing out a dangerous vapor: University of Utah engineers develop material that can sense fuel leaks and fuel-based explosives March 28th, 2016

Detecting and identifying explosives with single test December 10th, 2015

Military

Doubling down on Schrödinger's cat May 27th, 2016

Nanoscale Trojan horses treat inflammation May 24th, 2016

Programmable materials find strength in molecular repetition May 23rd, 2016

Rice de-icer gains anti-icing properties: Dual-function, graphene-based material good for aircraft, extreme environments May 23rd, 2016

Photonics/Optics/Lasers

Attosecond physics: A switch for light-wave electronics May 24th, 2016

Photon collisions: Photonic billiards might be the newest game! May 20th, 2016

We’ll Leave the Lights On For You: Photonics advances allow us to be seen across the universe, with major implications for the search for extraterrestrial intelligence, says UC Santa Barbara physicist Philip Lubin - See more at: http://www.news.ucsb.edu/2016/016805/we-ll-leave-li May 17th, 2016

UW researchers unleash graphene 'tiger' for more efficient optoelectronics May 16th, 2016

Research partnerships

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

The next generation of carbon monoxide nanosensors May 26th, 2016

Revealing the nature of magnetic interactions in manganese oxide: New technique for probing local magnetic interactions confirms 'superexchange' model that explains how the material gets its long-range magnetic order May 25th, 2016

Light can 'heal' defects in new solar cell materials: Defects in some new electronic materials can be removed by making ions move under illumination May 24th, 2016

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







Car Brands
Buy website traffic