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 New material could advance superconductivity
28.07.2016 | Carnegie Institution for Science

nachricht Dirty to drinkable
27.07.2016 | Washington University in St. Louis

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-assembling nano inks form conductive and transparent grids during imprint

Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.

To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...

Im Focus: The Glowing Brain

A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology

On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...

Im Focus: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

World first demo of labyrinth magnetic-domain-optical Q-switched laser

28.07.2016 | Information Technology

New material could advance superconductivity

28.07.2016 | Materials Sciences

CO2 can be stored underground for 10 times the length needed to avoid climatic impact

28.07.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>