[Paper Review] Kirigami Metamaterials for Reconfigurable Toroidal Circular Dichroism

Liqiao Jing, Zuojia Wang+7 more|arXiv (Cornell University)|Aug 31, 2018

Metamaterials and Metasurfaces Applications49 references3 citations

TL;DR

This paper proposes kirigami-based metamaterials that achieve reconfigurable toroidal circular dichroism by mechanically tuning split-ring resonator arrays through stretching. By exploiting multipoles—electric, magnetic, and toroidal—the design enables tunable single-band, dual-band, and broadband circular polarizers with maximum circular dichroisms of 0.88, 0.94, and 0.92, respectively, demonstrating mechanical control over chiral electromagnetic responses.

ABSTRACT

The ancient paper craft of kirigami has recently emerged as a potential tool for the design of functional materials. Inspired by the kirigami concept, we propose a class of kirigami-based metamaterials whose electromagnetic functionalities can be switched between nonchiral and chiral states by stretching the predesigned split-ring resonator array. Single-band, dual-band and broadband circular polarizers with reconfigurable performance are experimentally demonstrated with maximum circular dichroisms of 0.88, 0.94 and 0.92, respectively. The underlying mechanism is explained and calculated via detailed analysis of the excited multipoles, including the electric, magnetic, and toroidal dipoles and quadrupole. Our approach enables tailoring the electromagnetic functionalities in kirigami patterns and provides an alternate avenue for reconfigurable optical metadevices with exceptional mechanical properties.

Motivation & Objective

• To develop mechanically reconfigurable metamaterials with tunable chiral optical responses using kirigami principles.
• To overcome the limitations of fixed chiral metamaterials by enabling dynamic switching between nonchiral and chiral states.
• To explore the role of multipoles—especially toroidal dipole—under mechanical deformation in achieving reconfigurable circular dichroism.
• To demonstrate practical, experimentally realized circular polarizers with broadband and multi-band tunability.

Proposed method

• Design of a split-ring resonator array patterned with kirigami cuts to enable large-scale mechanical deformation.
• Use of mechanical stretching to dynamically reconfigure the geometry of the resonators, altering their electromagnetic response.
• Employment of full-wave simulations and scattering parameter analysis to characterize the electromagnetic response across different deformation states.
• Detailed multipole decomposition analysis to identify contributions from electric, magnetic, and toroidal dipoles and quadrupoles.
• Fabrication of physical prototypes using lithographic techniques for experimental validation of reconfigurable circular dichroism.
• Measurement of circular dichroism across multiple frequency bands to quantify tunability and performance.

Experimental results

Research questions

• RQ1 Can kirigami-inspired mechanical deformation dynamically switch a metamaterial between nonchiral and chiral states?
• RQ2 What is the role of toroidal dipole excitation in enabling reconfigurable circular dichroism in split-ring resonator arrays?
• RQ3 How does mechanical stretching affect the relative contributions of electric, magnetic, and toroidal multipoles in the resonant response?
• RQ4 Can broadband and multi-band reconfigurable circular polarizers be experimentally realized using this kirigami approach?
• RQ5 What is the maximum achievable circular dichroism in such mechanically tunable metamaterials?

Key findings

• The kirigami metamaterial achieves a maximum circular dichroism of 0.88 in single-band operation, demonstrating effective chiral filtering.
• Dual-band reconfigurable circular polarizers were experimentally demonstrated with a peak circular dichroism of 0.94, indicating high selectivity and tunability.
• Broadband circular polarizers were realized with a maximum circular dichroism of 0.92, showing performance across a wide frequency range.
• Multipole analysis confirmed that toroidal dipole contributions are significantly enhanced under mechanical deformation, driving the reconfigurable chiral response.
• The mechanical tunability enables reversible switching between nonchiral and chiral states, enabling dynamic control of circular polarization.
• The experimental results align well with full-wave simulations, validating the design and analysis framework.