Towards maximally electromagnetically chiral scatterers at optical frequencies
arXiv:2112.04422 · doi:10.1021/acsphotonics.1c01887
Abstract
Designing objects with predefined optical properties is a task of fundamental importance for nanophotonics, and chirality is a prototypical example of such a property, with applications ranging from photochemistry to nonlinear photonics. A measure of electromagnetic chirality with a well-defined upper bound has recently been proposed. Here, we optimize the shape of silver helices at discrete frequencies ranging from the far infrared to the optical band. Gaussian process optimization, taking into account also shape derivative information of the helices scattering response, is used to maximize the electromagnetic chirality. We show that the theoretical designs achieve more than 90 percent of the upper bound of em-chirality for wavelenghts \SI{3}{\micro\meter} or larger, while their performance decreases towards the optical band. We fabricate and characterize helices for operation at \SI{800}{\nano\meter}, and identify some of the imperfections that affect the performance. Our work motivates further research both on the theoretical and fabrication sides to unlock potential applications of objects with large electromagnetic chirality at optical frequencies, such as helicity filtering glasses. We show that, at \SI{3}{\micro\meter}, a thin slab of randomly oriented helices can absorb 99 percent of the light of one helicity while absorbing only 9 percent of the opposite helicity.
References in corpus (24)
- DNA-based Self-Assembly of Chiral Plasmonic Nanostructures with Tailored Optical Response
- Plasmonic Films Can Easily Be Better: Rules and Recipes
- Chiral plasmonics
- Electromagnetic duality symmetry and helicity conservation for the macroscopic Maxwell's equations (previously "Experimental demonstration of electromagnetic duality symmetry breaking")
- Adaptive Finite Element Method for Simulation of Optical Nano Structures
- Objects of maximum electromagnetic chirality
- Benchmarking five global optimization approaches for nano-optical shape optimization and parameter reconstruction
- Helicity-preserving optical cavity modes for enhanced sensing of chiral molecules
- Achiral, Helicity Preserving, and Resonant Structures for Enhanced Sensing of Chiral Molecules
- Forward-Mode Differentiation of Maxwell's Equations
- Circular Dichroism Enhancement in Plasmonic Nanorod Metamaterials
- Chiroptical response of a single plasmonic nanohelix
- Complete multipolar description of reflection and transmission across a metasurface for perfect absorption of light
- The resonant behavior of a single plasmonic helix
- Inverse design of optical elements based on arrays of dielectric spheres
- Isotropic Huygens dipoles and multipoles with colloidal particles
- Computation of electromagnetic properties of molecular ensembles
- Scattering matrix of arbitrarily shaped objects: Combining Finite Elements and Vector Partial Waves
- Decomposition of scattered electromagnetic fields into vector spherical wave functions on surfaces with general shapes
- Insights into broadband backscattering suppression in solar cells from the helicity preservation point of view
- Fast simulation method for parameter reconstruction in optical metrology
- Role of Geometric Shape in Chiral Optics
- Locally Enhanced and Tunable Optical Chirality in Helical Metamaterials
- An asymptotic representation formula for scattering by thin tubular structures and an application in inverse scattering