Giant Circular Dichroism and Negative Refractive Index of Chiral Metamaterial Based on Split-Ring Resonators

Abstract

Abstract-In this paper, a double-layer split-ring resonator structure chiral metamaterial was proposed which could exhibit pronounced circular dichroism (CD) effect and negative refractive index at microwave frequencies. Experiment and simulation calculations are in good agreement. The retrieved effective electromagnetic parameters indicate that the lower frequency CD effect is associated with the negative refractive index property of the left circularly polarized (LCP) wave, and the upper one is to the right circularly polarized (RCP) wave. The mechanism of the giant CD effect could be further illustrated by simulated surface current and power loss density distributions.

Dual-Band Circular Polarizer and Linear Polarization Transformer Based on Twisted Split-Ring Structure Asymmetric Chiral Metamaterial

“…CMMs are of great current interest both for customized functionalities and for potential applications not found in natural medium arise from the magneto-electric cross coupling of chiral structures due to their lack of any mirror symmetry. As a fact, besides negative refractive index, CMMs can also achieve other exotic EM characteristics, such as giant gyrotropy [4], strong polarization rotation (giant optical activity) [5][6][7][8][9][10][11], circular polarizer (circular dichroism, CD effect) [12][13][14][15], asymmetric transmission (AT) effect [16][17][18][19][20][21], linear or/to circular polarization conversion [22][23][24][25][26][27][28][29][30][31][32], and even the prospect of a repulsive Casimir force [33,34] by special enantiomeric forms or similar chiral structure design. The cross-coupling is original physics of these special electromagnetic (EM) properties [35,36].…”

Ultra-Compact Multi-Band Chiral Metamaterial Circular Polarizer Based on Triple Twisted Split-Ring Resonator

“…The front DSRR pattern is formed by rotating an enantiometric form of the back DSRR by 90 • . This construction law in our design distinguishes any previous design with only a mutual 90 • twist or with only an enantiometric form [3][4][5][6][7][8][9]. Thus, the chirality of the design can be further enhanced.…”

“…To go a step further, we will demonstrate our proposed CMMs numerically and experimentally for the multi-band circular polarization conversion. Since the split-ring resonators (SRRs) allow for a control and manipulation of EM (light) waves on sub-wavelength length scales [8,12,14,15,23], which is also employed as the basic element in our design. Figs.…”

“…Chiral metamaterials (CMMs) is lack of any mirror symmetry and also neither violates reciprocity nor time-reversal symmetry, which has been paid attention increasingly due to their exotic electromagnetic (EM) properties [1][2][3][4][5][6][7][8][9]. From microwave to optical ranges, negative refraction [1], giant gyrotropy [2], optical activity [3][4][5][6], circular dichroism (CD) [7][8][9], asymmetric transmission (AT) [10][11][12][13], and linear or/to circular polarization conversion [14][15][16] can be explored and realized by special CMM design.…”

“…From microwave to optical ranges, negative refraction [1], giant gyrotropy [2], optical activity [3][4][5][6], circular dichroism (CD) [7][8][9], asymmetric transmission (AT) [10][11][12][13], and linear or/to circular polarization conversion [14][15][16] can be explored and realized by special CMM design. Essentially, these unique EM properties mainly originate from cross-coupling of the electric and magnetic fields among these chiral structures [17][18][19][20][21][22][23].…”