Inverse design of Mie resonators with minimal backscattering.

Area of Science:

• Optics and Photonics
• Nanophotonics
• Computational Electromagnetics

Background:

• Controlling light scattering from nanostructures is crucial for advanced optical devices.
• Dielectric nanoantennas offer tunable light-matter interactions.
• Minimizing backscattering is key for applications like antireflective surfaces.

Purpose of the Study:

• To theoretically investigate and achieve suppressed backscattering in dielectric nanoantennas.
• To identify specific nanoantenna geometries that minimize backward scattering cross-section.
• To explore the relationship between nanoantenna shape, multipolar content, and optical properties.

Main Methods:

• Utilized the covariance matrix adaptation evolution strategy (CMA-ES) for optimization.
• Investigated axisymmetric dielectric structures.
• Employed clustering algorithms to analyze found geometries based on multipolar content.

Main Results:

• Identified multiple dielectric nanoantenna geometries with near-zero backscattering intensity.
• Achieved suppressed backscattering through the generalized Kerker effect and multipole cancellation.
• Demonstrated that diverse shapes can exhibit similar optical properties due to shared multipolar content.

Conclusions:

• Near-zero backscattering is achievable in dielectric nanoantennas via optimized geometries.
• The study reveals inherent ambiguities in free-form optimization of nanophotonic structures.
• Results provide a foundation for designing efficient antireflective metasurfaces and electromagnetic devices.