Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Single-pixel 'multiplex' captures elusive terahertz images

30.06.2014

Boston College, New Mexico and Duke researchers advance THz imaging using unique metamaterial

A novel metamaterial enables a fast, efficient and high-fidelity terahertz radiation imaging system capable of manipulating the stubborn electromagnetic waves, advancing a technology with potential applications in medical and security imaging, a team led by Boston College researchers reports in the online edition of the journal Nature Photonics.


Developed by a team of researchers from Boston College, the University of New Mexico and Duke University, a "multiplex" single pixel imaging process effectively tames stubborn terahertz (THz) light waves with electronic controls in a novel metamaterial. As the graphic shows, THz image waves are received by a metamaterial spatial light modulator, which in turn sends multiple data points from the THz scene to a single-pixel detector, which computationally reconstructs the image faster, more efficiently and with higher-fidelity than conventional THz imaging technology. Credit: Nature Photonics

The team reports it developed a "multiplex" tunable spatial light modulator (SLM) that uses a series of filter-like "masks" to retrieve multiple samples of a terahertz (THz) scene, which are reassembled by a single-pixel detector, said Boston College Professor of Physics Willie Padilla, a lead author of the report.

Data obtained from these encoded measurements are used to computationally reconstruct the images as much as six times faster than traditional raster scan THz devices, the team reports. In addition, the device employs an efficient low power source, said Padilla, whose research team worked with colleagues from the University of New Mexico and Duke University.

"I think we were surprised by how well the imaging system worked, particularly in light of the incredibly low power source," said Padilla. "Traditional THz imaging systems use sources that demand much more power than our system."

Metamaterials are designer electromagnetic materials that have tunable optical properties, allowing them to interact with light waves in new ways. Those unique properties have proven conducive to working with THz light waves, which have longer wavelengths than visible light and therefore require new imaging technology.

Padilla said the team set out to use metamaterials to develop an imaging architecture superior to earlier THz camera designs, which have relied on expensive and bulky detector arrays to assemble images.

Central to the team's advanced device is the development of a spatial light modulator constructed from a unique metamaterial structure by researchers at the University of New Mexico's Center for High Technology Materials. The SLM, which deploys a series of masks to obtain select image information from the THz scene, showed it effectively tames the otherwise stubborn THz light waves, which have defied other forms of frequency controls such as electronic sensors and semiconductor devices.

The metamaterial SLM efficiently modulates THz radiation when an electronically controlled voltage is applied between two layers of the metamaterial, effectively changing its optical properties and allowing it to actively display encoding masks designed to retrieve THz images. One such encoding technique allowed the researchers to access negative encoding values, which allow for higher fidelity image reconstruction.

A negative encoding value typically requires phase-sensitive sources and detectors, multiple detectors, or taking twice the number of measurements in order to create the image. The team created its "masks" without additional equipment or measurements, allowing researchers to use a more robust image encoding method that increased image quality while reducing the time needed to acquire the image.

Since it offers improved results without additional equipment, researchers engaged in "multiplexing" THz imaging could quickly adopt the new imaging approach. The findings add to a growing body of research that shows metamaterials are a viable option for the construction of efficient SLMs at THz wavelengths.

"In the long run, I think we set out a new paradigm for imaging at longer wavelengths," said Padilla. "Rather than including an expensive and bulky detector array in an imaging system, high-fidelity images can be obtained with only a single pixel detector and a low power source, allowing for a compact and inexpensive THz imaging system."

Padilla said a new generation of metamaterial THz imaging systems could help realize the potential applications projected by researchers and theorists.

"This type of imaging system has the potential to make a huge impact," said Padilla. "The ability to image a scene with THz could be used to screen for cancerous skin cells, monitor airports and other secure areas for illegal drugs or explosives, and perform personnel screening to look for concealed weapons."

###

In addition to Padilla, the research team included BC graduate students Claire M. Watts and David Shrenkenhamer and undergraduate Timothy Sleasman; University of New Mexico Professor Sanjay Krishna and graduate students; and Duke University Professor David R. Smith and graduate students, of the Center for Metamaterials and Integrated Plasmonics.

Ed Hayward | Eurek Alert!
Further information:
http://www.bc.edu

Further reports about: SLM THz detector detectors encoding measurements metamaterials properties spatial wavelengths waves

More articles from Materials Sciences:

nachricht Strange but true: Turning a material upside down can sometimes make it softer
20.10.2017 | Universitat Autonoma de Barcelona

nachricht Metallic nanoparticles will help to determine the percentage of volatile compounds
20.10.2017 | Lomonosov Moscow State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>