Electrogyration in Metamaterials: Chirality and Polarization Rotatory Power that Depend on Applied Electric Field. Issue 4 (16th December 2020)

• Record Type: Journal Article
• Authors: Zhang, Qiang; Plum, Eric; Ou, Jun‐Yu; Pi, Hailong; Li, Junqing; MacDonald, Kevin F.; Zheludev, Nikolay I.
• Is Part Of: Advanced optical materials. Volume 9:Issue 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-16
• Subjects: chirality -- electrogyration -- electro‐optic effect -- metamaterials -- nanoelectromechanical systems -- optical activity; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202001826
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: One of the most fascinating properties of chiral molecules is their ability to rotate the polarization of light. Since Faraday's experiments in 1845, it has been known that nonreciprocal polarization rotatory power can be induced by a magnetic field. But can reciprocal polarization rotation in chiral molecules be influenced by an electric field? In the 1960s, Aizu and Zheludev introduced the phenomenon of electrogyration. While the linear (Pockels) and quadratic (Kerr) electro‐optical effects describe how an external electric field changes linear birefringence and dichroism, electrogyration describes how a field changes the circular birefringence and dichroism of a medium. Electrogyration is observed in dielectrics, semiconductors, and ferroelectrics, but the effect is small. This work demonstrates a nanostructured photonic metamaterial that exhibits quadratic electrogyration—proportional to the square of the applied electric field—six orders of magnitude stronger than in any natural medium. Giant quadratic electrogyration emerges as electrostatic forces acting against forces of elasticity change the chiral configuration of the metamaterial's nanoscale building blocks and consequently its polarization rotatory power. This observation of giant electrogyration alters the perception of the effect from that of an esoteric phenomenon into a functional part of the electro‐optic toolkit with application potential. Abstract : Electrogyration, the dependence of optical activity on electric field, is a weak effect in naturally occurring materials. Co‐engineering of optical and nanomechanical properties enables the realization of a photonic metamaterial structure manifesting giant electrogyration, a million times stronger than in any natural medium. Electric field actuates the nanostructure, changing its handedness and controlling both magnitude and sign of optical activity.