Enhanced Diffractive Circular Dichroism from Stereoscopic Plasmonic Molecule Array

Artificial nanostructures with large optical chiral responses have been intensively investigated recently. In this work, we propose a diffractive circular dichroism enhancement technique using stereoscopic plasmonic molecule structures. According to the multipole expansion analysis, the z-component of the electric dipole becomes the dominant chiral scattering mechanism during the interaction between an individual plasmonic molecule and the plane wave at a grazing angle. For a periodical structure with the designed plasmonic molecule, large diffractive circular dichroism can be obtained, which can be associated with the Wood-Rayleigh anomaly. Such a diffractive circular dichroism enhancement is verified by the good agreement between numerical simulations and experimental results. The proposed approach can be potentially used to develop enhanced spectroscopy techniques to measure chiral information, which is very important for fundamental physical and chemical research and bio-sensing applications.

Automated summary

In this work, a diffractive circular dichroism enhancement technique using stereoscopic plasmonic molecule structures is proposed. The dominant chiral scattering mechanism is identified as the z-component of the electric dipole during the interaction between an individual plasmonic molecule and a grazing plane wave. Through the design of periodic plasmonic molecule structures, large diffractive circular dichroism can be achieved, which is validated by numerical simulations and experimental results. The proposed approach has potential application in enhanced spectroscopy techniques for measuring chiral information, crucial for fundamental physical and chemical research as well as bio-sensing applications.