Microscopes help us examine, understand, and improve materials, medicines, and organisms at some of the smallest levels imaginable.
Telescopes help us look into the farthest reaches of space, unlocking some of the mysteries of the universe.
Despite differences in measurement several million times over, both microscopes and telescopes owe their functionality to a key piece of physics: optics.
In simple terms, optics is the study of light, its interactions with materials, its properties, and its uses, impacting everything from the aforementioned scopes to sensors, communications, and even simple mirrors.
One such use is the ability to use the optics of a material to help identify it, often with a technique known as surface plasmon resonance or SPR. By measuring the properties within a beam spot, SPR can help perform a chemical analysis and identify the target material.
This technique, though versatile, cannot measure optical properties of a material at nanoscale and provides an average result over a diffraction-limited beam spot. Near-field optical microscopes, on the other hand, can provide nanoscale images of a sample but lack the ability to provide optical properties at that scale.
Thanks to research conducted by a recent graduate from UT’s Min H. Kao Department of Electrical Engineering and Computer Science, that could soon change.
“The surface plasmon scanning tunneling microscope (SPSTM) takes a new approach to chemical mapping at nanoscale levels,” said Vineet Khullar, who worked on the project while a UT student along with EECS Professor Gong Gu, Department of Physics and Astronomy Research Professor Thomas Ferrell, and Oak Ridge National Laboratory staff scientist Ali Passian.
“The imaging capability results from the exponential decay of the evanescent field of surface plasmon modes. By splitting the fiber, part of the signal can be directed to the spectrophotometer to help perform surface plasmon-assisted spectroscopy, and an addition of a chemical map over the topographical image is a unique feature of SPSTM.”
In addition to potentially adding chemical maps, Khullar said, the breakthrough will allow researchers to surpass current optical microscopes and produce chemical maps at much higher resolution than has been previously possible.
As a sign of the importance of the breakthrough, the technique was recently awarded a patent by the US Patent and Trademark Office.
David Goddard (865-974-0683, email@example.com)