“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 firstname.lastname@example.org.
The paper, “All-Semiconductor Plasmonic Nanoantennas for Infrared Sensing,” is available online or from the U. of I. News Bureau.
Liz Ahlberg | Source: University of Illinois
Further information: www.illinois.edu
More articles from Physics and Astronomy:
CU-Boulder scientist: 2012 solar storm points up need for society to prepare
10.12.2013 | University of Colorado at Boulder
3D printing used as a tool to explain theoretical physics
09.12.2013 | Institute of Physics
The molecular architecture of three key proteins and their complexes reveals how plants fine-tune their immune response to pathogens
Plants rarely get sick in their natural environment. When the threat of infection arises, a quick decision is made about the necessary countermeasures. The course is set by a protein which forms complexes with its partner proteins for this purpose.
Jane Parker from the Max Planck Institute for Plant Breeding ...
Researchers studying speciation of butterfly orchids on the Azores have been startled to discover that the answer to a long-debated question "Do the islands support one species or two species?" is actually "three species".
Hochstetter's Butterfly-orchid, newly recognized following application of a battery of scientific techniques and reveling in a complex taxonomic history worthy of Sherlock Holmes, is arguably Europe's rarest orchid species. Under threat in its mountain-top retreat, the orchid urgently requires conservation recognition.
A lavishly illustrated publication, titled "Systematic revision of Platanthera in ...
Researchers from Brown University and the University of Hawaii have found some mineralogical surprises in the Moon's largest impact crater.
Data from the Moon Mineralogy Mapper that flew aboard India's Chandrayaan-1 lunar orbiter shows a diverse mineralogy in the subsurface of the giant South Pole Aitken basin.
The differing mineral signatures could be reflective of the minerals dredged up at the time of the giant impact 4 billion years ago, ...
In power electronics systems bonded connections create the central electrical connections between adjoining surfaces.
The quality of these bonded connections is one of the main factors that determines the reliability and availability of drive systems in electric vehicles, and hence constitutes a major design challenge for German auto manufacturers aiming to electrify their vehicles.
Now the partners participating in the RoBE (Robust Bonds in ...
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
11.12.2013 | Information Technology
11.12.2013 | Life Sciences
11.12.2013 | Agricultural and Forestry Science
11.12.2013 | Event News
10.12.2013 | Event News
05.12.2013 | Event News