ITMO Researchers Make Inroads in Optimizing Nanoparticles’ Response to Light

Physicists from ITMO University have discovered new features of dielectric nanoparticles’ optical response using an improved method for electromagnetic field analysis that can take into account more complex configurations of bias currents inside the objects. These effects help to better understand the processes in nanoparticles and adjust their behavior for more efficient light control in devices such as nanolasers or sensors. The researchers showed that there are complex configurations of displacement currents inside the particle, which lead to toroidal moments of higher orders, and that the complex interaction of currents in a particle can switch it into a special nonradiative state. These results could lead to the development of more efficient devices. Alexander Shalin, head of the International Scientific Laboratory Nano-Optomechanics of ITMO University, compared the science to a mechanism that can be adjusted to different modes of operation using different gears. “A multipole is the same gear for a particle,” he said. “Particles of complex shape, as complex mechanisms, can perform more different tasks. But they have more gears, and due to lack of information about them, it was impossible to control the work of such particles earlier.” Recently, dielectric nanoparticles have been actively used to control light at nanoscale. They behave better than previously proposed plasmon particles, avoid energy loss, and obtain interesting physical effects, meaning that dielectric particles can be used, for example, to create nanolasers, nanoantennas, sensors, or information transfer devices. Scientists are trying to study their behavior in detail to apply them effectively. The research was published in Laser & Photonics Reviews (https://doi.org/10.1002/lpor.201800266).