“The identification of molecules by sensing their unique absorption resonances is very important for environmental monitoring, industrial process control and military applications,” said team leader Daniel Wasserman, a professor of electrical and computer engineering. Wasserman is also a part of the Micro and Nano Technology Laboratory at Illinois.
The food and pharmaceutical industries use light to detect contaminants and to ensure quality. The light interacts with the bonds in the molecules, which resonate at particular frequencies, giving each molecule a “spectral fingerprint.” Many molecules and materials more strongly resonate in the IR end of the spectrum, which has very long wavelengths of light – often larger than the molecules themselves.
“The absorption signatures of some of the molecules of interest for these applications can be quite weak, and as we move to nano-scale materials, it can be very difficult to see absorption from volumes smaller than the wavelength of light,” Wasserman said. “It is here that our antenna array surfaces could have a significant impact.”
Other nano-scale antenna systems cannot be tuned to a longer light wavelength because of the limitations of traditional nanoantenna materials. The Illinois team used highly doped semiconductors, grown by a technique called molecular beam epitaxy that is used to make IR lasers and detectors.
“We have shown that nanostructures fabricated from highly doped semiconductors act as antennas in the infrared,” said Stephanie Law, a postdoctoral researcher at Illinois and the lead author of the work. “The antennas concentrate this very long wavelength light into ultra-subwavelength volumes, and can be used to sense molecules with very weak absorption resonances.”
The semiconductor antenna arrays allow long-wavelength light to strongly interact with nano-scale samples, so the arrays could enhance the detection of small volumes of materials with a standard IR spectrometer – already a commonplace piece of equipment in many industrial and research labs.
The researchers further demonstrated their ability to control the position and strength of the antenna resonance by adjusting the nanoantenna dimensions and the semiconductor material properties.
The group will continue to explore new shapes and structures to further enhance light-matter interaction at very small scales and to potentially integrate these materials with other sensing systems.
“We are looking to integrate these antenna structures with optoelectronic devices to make more efficient, smaller, optoelectronic components for sensing and security applications,” Wasserman said.
Editor’s notes: To reach Daniel Wasserman, call 217-333-9872; email email@example.com.
The paper, “All-Semiconductor Plasmonic Nanoantennas for Infrared Sensing,” is available online or from the U. of I. News Bureau.
Liz Ahlberg | University of Illinois
New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center
Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology
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...
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....
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...
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...
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...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Earth Sciences
20.10.2017 | Life Sciences
20.10.2017 | Life Sciences