Nanoscale manipulation of light leads to exciting new advancement

October 11, 2019

Controlling the interactions between light and matter has been a long-standing ambition for scientists seeking to develop and advance numerous technologies that are fundamental to society. With the boom of nanotechnology in recent years, the nanoscale manipulation of light has become both, a promising pathway to continue this advancement, as well as a unique challenge due to new behaviors that appear when the dimensions of structures become comparable to the wavelength of light.

Scientists in the Theoretical Nanophotonics Group at The University of New Mexico's Department of Physics and Astronomy have made an exciting new advancement to this end, in a pioneering research effort titled "Analysis of the Limits of the Near-Field Produced by Nanoparticle Arrays," published recently in the journal, ACS Nano, a top journal in the field of nanotechnology.

The group, led by Assistant Professor Alejandro Manjavacas, studied how the optical response of periodic arrays of metallic nanostructures can be manipulated to produce strong electric fields in their vicinity.

The arrays they studied are composed of silver nanoparticles, tiny spheres of silver that are hundreds of times smaller than the thickness of a human hair, placed in a repeating pattern, though their results apply to nanostructures made of other materials as well. Because of the strong interactions between each of the nanospheres, these systems can be used for different applications, ranging from vivid, high-resolution color printing to biosensing that could revolutionize healthcare.

"This new work will help to advance the many applications of nanostructure arrays by providing fundamental insights into their behavior," says Manjavacas. "The near-field enhancements we predict could be a game changer for technologies like ultrasensitive biosensing."

Manjavacas and his team, composed of Lauren Zundel and Stephen Sanders, both graduate students in the Department of Physics and Astronomy, modeled the optical response of these arrays, finding exciting new results. When periodic arrays of nanostructures are illuminated with light, each of the particles produces a strong response, which, in turn, results in enormous collective behaviors if all of the particles can interact with one another. This happens at certain wavelengths of incident light, which are determined by the interparticle spacing of the array, and can result in electric fields that are thousands, or even tens of thousands, of times that of the light shined on the array.

The strength of this field enhancement depends on the geometrical properties of the array, such as the spacing between the nanospheres, as well as the size of the spheres themselves. Completely counterintuitively, Manjavacas and his group found that decreasing the density of nanoparticles in the array, either by increasing the spacing between each of them, or by decreasing their size, produces field enhancements that are not only larger, but extend farther away from the array.

"It was really exciting to find out that the key to these huge field enhancements actually lies in making the particles smaller and farther apart," says Zundel of the discovery.

"The reason for this is that the interactions between the nanoparticles, and thus the collective response, is strengthened," according to Sanders.
-end-
The research was sponsored in part by the National Science Foundation (NSF) and made use of the high-performance computational resources made available by the UNM Center for Advanced Research Computing.

University of New Mexico

Related Nanoparticles Articles from Brightsurf:

An ionic forcefield for nanoparticles
Nanoparticles are promising drug delivery tools but they struggle to get past the immune system's first line of defense: proteins in the blood serum that tag potential invaders.

Phytoplankton disturbed by nanoparticles
Products derived from nanotechnology are efficient and highly sought-after, yet their effects on the environment are still poorly understood.

How to get more cancer-fighting nanoparticles to where they are needed
University of Toronto Engineering researchers have discovered a dose threshold that greatly increases the delivery of cancer-fighting drugs into a tumour.

Nanoparticles: Acidic alert
Researchers of Ludwig-Maximilians-Universitaet (LMU) in Munich have synthesized nanoparticles that can be induced by a change in pH to release a deadly dose of ionized iron within cells.

3D reconstructions of individual nanoparticles
Want to find out how to design and build materials atom by atom?

Directing nanoparticles straight to tumors
Modern anticancer therapies aim to attack tumor cells while sparing healthy tissue.

Sweet nanoparticles trick kidney
Researchers engineer tiny particles with sugar molecules to prevent side effect in cancer therapy.

A megalibrary of nanoparticles
Using straightforward chemistry and a mix-and-match, modular strategy, researchers have developed a simple approach that could produce over 65,000 different types of complex nanoparticles.

Dialing up the heat on nanoparticles
Rapid progress in the field of metallic nanotechnology is sparking a science revolution that is likely to impact all areas of society, according to professor of physics Ventsislav Valev and his team at the University of Bath in the UK.

Illuminating the world of nanoparticles
Scientists at the Okinawa Institute of Science and Technology Graduate University (OIST) have developed a light-based device that can act as a biosensor, detecting biological substances in materials; for example, harmful pathogens in food samples.

Read More: Nanoparticles News and Nanoparticles Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.