Superchiral Light Generation on Degenerate Achiral Surfaces

Area of Science:

• Plasmonics
• Chirality
• Nanophotonics

Background:

• Chiral light generation typically requires complex chiral nanostructures.
• Existing methods for detecting molecular chirality often lack sensitivity and suffer from background noise.

Purpose of the Study:

• To demonstrate a novel route for generating superchiral near fields from geometrically achiral systems.
• To enable background-free and highly sensitive detection of molecular chirality.

Main Methods:

• Utilizing geometrically achiral systems supporting degenerate and spatially superimposed plasmonic modes.
• Theoretical elucidation using a rotating dipole model.
• Experimental demonstration of molecular chirality detection.

Main Results:

• Generation of a single-handed chiral near field with zero far-field circular dichroism.
• Prediction and observation of near-field handedness flipping solely by reversing the source handedness.
• Achieved approximately four orders of magnitude enhancement in detection sensitivity for molecular chirality.

Conclusions:

• The demonstrated method provides a novel and efficient pathway for generating superchiral near fields.
• This technique offers a powerful tool for background-free and highly sensitive detection of molecular chirality through near-field light-matter interactions.