Optical activity and coupling in twisted dimer meta-atoms

Mingkai Liu*, David A. Powell, Ilya V. Shadrivov, Yuri S. Kivshar

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    39 Citations (Scopus)

    Abstract

    We analyse the optical activity in twisted dimers, the meta-atoms of a chiral metamaterial, by introducing a simple yet accurate model for the coupling between them. The near-field interaction coefficients are derived from a Lagrangian model and include the effects of retardation, whereas the far-field radiation is based on a multipole expansion. We show that the optimum twist angle varies with frequency, and near resonance is substantially lower than 45 degrees, which is the lowest symmetry configuration. Our approach is accurate over a wide frequency range, including the resonant regions with the highest optical activity. In contrast to other models of near-field interaction, it requires no fitted parameters or homogenization procedure and is directly applicable to a wide variety of resonant particles.

    Original languageEnglish
    Article number111114
    JournalApplied Physics Letters
    Volume100
    Issue number11
    DOIs
    Publication statusPublished - 12 Mar 2012

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