Controlling the interactions between light and matter has long been a concern of scientists who want to develop and develop many of the basic technologies for society. With the boom of nanotechnology in recent years, nanoscale manipulation of light is both a promising way to continue this progress and a unique challenge due to new behaviors that occur when the dimensions of structures are comparable to the wavelength of light.
Scientists from the Theoretical Nanophotonics group at the University of New Mexico's Institute of Physics and Astronomy have made exciting new progress in a ground-breaking research effort titled "Analyzing the Borders of the Nanoparticle Array-Generated Near Field". recently published in the journal ACS Nano a leading journal in the field of nanotechnology, led by Assistant Professor Alejandro Manjavacas, investigated how the optical response of periodic arrays of metallic nanostructures can be manipulated to generate strong electric fields in
The arrangements studied consist of silver nanoparticles, tiny silver spheres hundreds of times smaller than the thickness of a human hair, arranged in a repeating pattern, although their results are also applicable to nanostructures apply, which consist of other materials. Due to the strong interaction between the individual nanospheres, these systems can be used for a variety of applications, from vibrant, high-resolution color prints to biosensors that could revolutionize healthcare.
"This new work will help advance the numerous applications of nanostructure arrays by providing fundamental insights into their behavior," says Manjavacas. "The near-field enhancements that we predict could be crucial for technologies such as ultrasensitive biosensors."
Manjavacas and his team, consisting of Lauren Zundel and Stephen Sanders, both graduate students of the Faculty of Physics and Astronomy, modeled the optics response of these arrays to find exciting new results. When periodic arrays of nanostructures are illuminated with light, each of the particles generates a strong response, which in turn leads to tremendous collective behavior when all the particles can interact with each other. This happens at certain wavelengths of incident light, as determined by the particle spacing of the array, and can result in electric fields that are thousands or even tens of thousands times larger than that of the light incident on the array.
The strength of this field enhancement depends on the geometric properties of the array, such as the distance between the nanospheres and the size of the spheres themselves. On the contrary, Manjavacas and his group found that reducing the density of nanoparticles in the array, either by increasing the distance between them or by reducing their size, causes field enhancements that are not only larger, but move farther away from the array.
"It was really exciting to find that the key to these tremendous field enhancements is to keep the particles smaller and farther apart," Zundel says of the discovery.
"The reason for this is the interactions between the nanoparticles and thus the collective reaction is strengthened," says Sanders.
Theoretical physicists manipulate light with nanoscale objects
Alejandro Manjavacas et al. Analysis of the boundaries of the near field generated by nanoparticle arrays, ACS Nano (201
Nanoscale manipulation of light leads to exciting new developments (2019, 9 October)
retrieved on October 9, 2019
This document is subject to copyright. Apart from any fair dealings for the purpose of private learning or research, no
Part may be reproduced without written permission. The content is for informational purposes only.