A ‘molecule scanner’ — world’s smallest teraHertz detector
August 7, 2013
The detector may have the ability to chemically identify single molecules using terahertz radiation — a range of light far lower in frequency (0.1 to 30 THz) than visible light but higher than microwaves.
Terahertz radiation is commonly used in airport scanners. It can reveals a wealth of information that is relevant for material, biological, and medical sciences with applications that span chemical sensing, high-speed electronics, and coherent control of semiconductor quantum bits, according to the researchers. However; it has been hard to apply to individual molecules.
Study coauthor Jeremy Levy, professor in the Department of Physics and Astronomy within the Kenneth P. Dietrich School of Arts and Sciences, and associates report both generation and detection of a broadband terahertz ﬁeld from 10-nm-scale LaAlO3
/SrTiO3 oxide nanojunctions.
Frequency components of ultrafast optical radiation are mixed at these nanojunctions, producing broadband THz emission. These same devices detect THz electric ﬁelds with comparable spatial resolution
The terahertz radiation is generated and detected with the help of an ultrafast laser, which is a pulsed light that turns on and off in less than 30 femtoseconds (10-15 second).
“We believe it would be possible to isolate and probe single nanostructures and even molecules — performing ‘terahertz spectroscopy’ at the ultimate level of a single molecule,” said Levy. “Such resolution will be unprecedented and could be useful for fundamental studies as well as more practical applications.”
Levy and his team are currently performing spectroscopy of molecules and nanoparticles. In the future, they hope to work with a C60, a well-known molecule, within the terahertz spectrum.
The University of Wisconsin-Madison was also involved in the research.