Chiral optical fields: A unified formulation of helicity scattered from particles and dichroism enhancement

Abstract

We establish a general unified formulation which, using the optical theorem of electromagnetic helicity, shows that dichorism is a phenomenon arising in any scattering -or diffraction- process, elastic or not, of chiral electromagnetic fields by objects either chiral or achiral. It is shown how this approach paves the way to overcoming well-known limitations of standard circular dichroism, like its weak signal or the difficulties of using it with magnetodielectric particles. Based on the angular spectrum representation of optical fields with only right circular or left circular plane waves, we introduce beams with transverse elliptic polarization and posessing a longitudinal component. Then our formulation for general optical fields shows how to enhance the extinction rate of incident helicity, (and therefore the dichroism signal), versus that of energy of the light scattered or emitted by a particle, or viceversa.

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Cited by in corpus (15)

• Twisted-ligth--ion interaction: the role of longitudinal fields
• Spin-orbit interactions and chiroptical effects engaging orbital angular momentum of twisted light in chiral and achiral media
• Orbital-to-Spin Angular Momentum Conversion Employing Local Helicity
• Kelvin's Chirality of Optical Beams
• Optimally Chiral Electromagnetic Fields: Helicity Density and Interaction of Structured Light with Nanoscale Matter
• Helicity Density Maximization in a Planar Array of Achiral High-Density Dielectric Nanoparticles
• Momentum-space geometric structure of helical evanescent waves and its implications on near-field directionality
• Optical Chirality of Time-Harmonic Wavefields for Classification of Scatterers
• Mimicking Chiral Light-Matter Interaction
• Helicity Maximization Below the Diffraction Limit
• Helicity Maximization of Structured Light to Empower Nanoscale Chiral Matter Interaction
• Non-zero helicity extinction in light scattered from achiral (or chiral) small particles located at points of null incident helicity density
• Fundamentals and model of resonance helicity and energy transfer between two magnetoelectric chiral particles
• Chiral scatterers designed by Bayesian optimization
• The electromagnetic scalar product in spatially-bounded domains