As COVID-19, which has claimed millions of lives, spreads around the world this year, an important factor in controlling its spread is the ability to quickly and accurately test the cause of the virus, SARS-CoV-2, as well as the production of antibodies.

Now, scientists at the University of New Mexico and the Autonomous University of Spain (UAM) have published a new study that could help test viruses such as SARS-CoV-2 quickly and effectively. Published in the journal “Super-subradiated lattice resonances in bipartite nanoparticle arrays” ACS Nano.

This work is led by Alejandro Manzawakas, Assistant Professor in the Theoretical Nanophotonics Group of the UN Department of Physics and Astronomy, and Antonio Fernandez-Domangius from UAM, in the field of nanophotonics. In the order of hundreds of nanometers. For reference, the thickness of human hair is approximately 40,000 nm, while the size of the virus produced by Kovid-19 is 125 nm.

Many applications of Nanophotonics, Including ultrasonic biosensing needed to detect viruses such as SARS-CoV-2, and nanoscale lacing, which can be used to produce attractive light of the desired color, relying on systems that respond only to very narrow colors, or in other words, wavelengths of light. One way to design systems with similarly spectral narrow reactions is to utilize a collection of metal nanoparticles, small structures of nanoscale dimensions, and collective interactions arranged in an order called a recurring array.

The researchers looked at periodic arrays consisting of nanoparticles of two different sizes, rather than more general configurations that contain fully integrated features.

“The interaction between two different nanoparticles results in narrower reactions than arrays of particles of the same size,” says Alvaro Quartero-Gonzalez, a graduate student from UAM and the lead author of the paper. “Also, as an added bonus, it is more robust to fabricated imperfections, so arrays with the desired response can be easily built in labs.”

This increased power will make a big difference when it comes to the massive production of tests or other devices that utilize the optical response of these systems.

This exciting work involves semi-analytical calculations and rigorous numerical simulations, carried out in collaboration with three undergraduate students Quartero-Gonzalez, Stephen Sanders and Lauren Sundel, who visited UNM from September 2019 to February 2020. From the UNM Department of Physics and Astronomy.

“Our semi-analytical predictions provide insight into the physics behind our results, while numerical calculations help confirm their validity,” Sanders said of the book. “The key to understanding system robustness lies in our calculations for limited systems,” Sandal added.

“Combining the expertise of the two groups was essential to the success of this work,” said Manjavakas, of Cooperation.

Fernandez-Domen‌guez admits, “I hope this is just the beginning of a number of collaborative efforts between us.”