Next-generation nanophotonics devices and applications come into view

Densely-packed solar cells that fit on a car and efficiently transfer light to electricity; point-of care medical diagnostic tools; major advances in communication, sensing and imaging – all of these plus many more depend on interaction of light with the material world at a very small scale, also known as nanophotonics.

What makes nanophotonics so interesting to scientists and so promising across a broad array of industry is the subject of a new platform patent filed by University of Georgia physicists and described in a new research study published Nature Communications: a method to access to strong light-matter interaction properties and new functionalities far beyond those available in natural materials.

“Controlling and shaping the properties of light is the key to developing electronic and light-based devices as well as secure and instant communication capabilities,” said Yohannes Abate, Susan Dasher and Charles Dasher MD Professor of Physics in the UGA Franklin College of Arts and Sciences and lead author on the new paper. “We demonstrated a new way of controlling and confining light-matter particles towards potential applications in electronics and optics.”

Within the vast possibilities of potential applications using light-based technologies in efficient communication at the nanoscale, is just one example. Finding ways to control light at a much smaller scale than what is possible by any conventional focusing methods has been a key focus for scientific and technological developments in the field of nanophotonics.

The focus of the new paper is an exotic process that creates and controls a diffraction unlimited light source, where the travelling wave is much smaller than that of the light beam. New materials that harness the properties of light-matter interaction are key towards realizing the myriad potentials of nanophotonics. The new research shows control and manipulation of propagating hybrid light-matter particles called polaritons. The work introduces a configurable polaritonic platform enabling nanoscale active control of polaritons.

Because focusing light by any kind of conventional lens is severely limited by diffraction, the ability to make light-based very small compact devices is not possible, whereas diffraction unlimited quasi-particles like polaritons will break the diffraction limit. And this capability will enable the ability to enhance light collection efficiencies and the fabrication of nanophotonic devices.

“For example, imaging the movement of few atoms (vibration) selectively in a large-scale material is challenging, you cannot do that with light. Instead, by breaking the diffraction limit, using polaritons, you can measure vibrational modes of molecules and atom-to-atom interactions at the relevant nanometer scale,” Abate said.

With such novel methods, it’s possible for scientists and engineers to again push back the boundaries dictated by conventional but less efficient lens-based devices.

“Nanophotonics – confining and controlling the flow of light at the nanoscale – is an exciting phenomenon, we show for the first time controllable and confined polaritons and this paves the way for more new things to come – novel devices and new things to learn about nature,” Abate said.

The research was performed in close collaboration with Purdue University, Kansas State University, University of Melbourne, RMIT University Australia, Kansas State University and CUNY Advanced Science Research Center. The full study is available online.

Image: Perovskite solar cell, courtesy of National Renewable Energy Laboratory.