Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New 'T-ray' tech converts light to sound for weapons detection, medical imaging

20.05.2014

A device that essentially listens for light waves could help open up the last frontier of the electromagnetic spectrum—the terahertz range.

So-called T-rays, which are light waves too long for human eyes to see, could help airport security guards find chemical and other weapons. They might let doctors image body tissues with less damage to healthy areas. And they could give astronomers new tools to study planets in other solar systems. Those are just a few possible applications.

But because terahertz frequencies fall between the capabilities of the specialized tools presently used to detect light, engineers have yet to efficiently harness them. The U-M researchers demonstrated a unique terahertz detector and imaging system that could bridge this terahertz gap.

"We convert the T-ray light into sound," said Jay Guo, U-M professor of electrical engineering and computer science, mechanical engineering, and macromolecular science and engineering. "Our detector is sensitive, compact and works at room temperature, and we've made it using an unconventional approach."

The sound the detector makes is too high for human ears to hear.

The terahertz gap is a sliver between the microwave and infrared bands of the electromagnetic spectrum—the range of light's wavelengths and frequencies. That spectrum spans from the longest, low-energy radio waves that can carry songs to our receivers to the shortest, high-energy gamma rays that are released when nuclear bombs explode and radioactive atoms decay.

In between are the microwave frequencies that can cook food or transport cell phone signals, the infrared that enables heat vision technologies, the visible wavelengths that light and color our world, and X-rays that give doctors a window under our skin.

The terahertz band is "scientifically rich," according to Guo and colleagues. But today's detectors either are bulky, need to be kept cold to work or can't operate in real time. That limits their usefulness for applications like weapons and chemical detection and medical imaging and diagnosis, Guo says.

Guo and colleagues invented a special transducer that makes the light-to-sound conversion possible. A transducer turns one form of energy into another. In this case it turns terahertz light into ultrasound waves and then transmits them.

The transducer is made of a mixture of a spongy plastic called polydimethylsiloxane, or PDMS, and carbon nanotubes. Here's how it works:

When the terahertz light hits the transducer, the nanotubes absorb it, turning it into heat. They pass that heat on to the PDMS. The heated PDMS expands, creating an outgoing pressure wave. That's the ultrasound wave. It's more than 1,000 times too high for human ears to pick up.

"There are many ways to detect ultrasound," Guo said. "We transformed a difficult problem into a problem that's already been solved."

Though ultrasound detectors exist—including those used in medical imaging—the researchers made their own sensitive one in the form of a microscopic plastic ring known as a microring resonator. The structure measures only a few millimeters in size.

They connected their system to a computer and demonstrated that they could use it to scan and produce an image of aluminum cross.

The response speed of the new detector is a fraction of a millionth of a second, which Guo says can enable real-time terahertz imaging in many areas.

The system is different from other heat-based terahertz detection systems because it responds to the energy of individual terahertz light pulses, rather than a continuous stream of T-rays. Because of this, it isn't sensitive to variations in the outside temperature, Guo says.

###

The study, "Efficient real-time detection of terahertz pulse radiation based on photoacoustic conversion by carbon nanotube nanocomposite," is published online in Nature Photonics. The research is funded by the National Science Foundation and the Air Force Office of Scientific Research.

Jay Guo: http://www.guogroup.org

Nicole Casal Moore | Eurek Alert!
Further information:
http://www.umich.edu

Further reports about: PDMS T-ray T-rays detector detectors frequencies hear plastic sensitive temperature wavelengths waves

More articles from Physics and Astronomy:

nachricht From the cosmos to fusion plasmas, PPPL presents findings at global APS gathering
13.11.2018 | DOE/Princeton Plasma Physics Laboratory

nachricht A two-atom quantum duet
12.11.2018 | Institute for Basic Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection

13.11.2018 | Life Sciences

Fish recognize their prey by electric colors

13.11.2018 | Life Sciences

Ultrasound Connects

13.11.2018 | Awards Funding

VideoLinks
Science & Research
Overview of more VideoLinks >>>