Generation of Optical Chirality Patterns with Plane Waves, Evanescent Waves and Surface Plasmon Waves

TL;DR

This paper presents a systematic analytical and numerical study of generating structured optical chirality patterns using plane waves, evanescent waves, and surface plasmon waves, with potential applications in chiral sensing.

Contribution

It derives general analytical solutions for optical chirality patterns in three different wave scenarios and verifies them through simulations, highlighting conditions for enhancement.

Findings

Structured chirality patterns can be generated with proper polarization and propagation.

Optical chirality enhancement occurs via constructive interference of specific waves.

Surface plasmon waves require high near-field intensity for chirality enhancement.

Abstract

We systematically investigate the generation of optical chirality patterns by applying the superposition of two waves in three scenarios, namely plane waves in free space, evanescent waves of totally reflected light at dielectric interface and propagating surface plasmon waves on a metallic surface. In each scenario, the general analytical solution of the optical chirality pattern is derived for different polarization states and propagating directions of the two waves. The analytical solutions are verified by numerical simulations. Spatially structured optical chirality patterns can be generated in all scenarios if the incident polarization states and propagation directions are correctly chosen. Optical chirality enhancement can be obtained from the constructive interference of free-space circularly polarized light or enhanced evanescent waves of totally reflected light. Surface plasmon waves do not provide enhanced optical chirality unless the near-field intensity enhancement is sufficiently high. The structured optical chirality patterns may find applications in chirality sorting, chiral imaging and circular dichroism spectroscopy.