A frequency-tunable 90°-polarization rotation device using composite chiral metamaterials

Abstract

We theoretically study the transmission properties of a stack of metallic metama-terials and show that is able to achieve a perfect transmission selectively exhibiting broadband (Q< 10) or extremely narrowband (Q> 10 5) polarization rotation. We especially highlight how the arrangement of the stacked structure, as well as the metamaterial unit cell geometry, can highly influence the transmission in the spectral domain. For this purpose, we use an extended analytical Jones formalism that allows us to get a rigorous and analytical expression of the transmission. Such versatile structures could find potential applications in polarimetry or in the control of the light polarization for THz waves. a)

Selective wave-transmitting electromagnetic absorber through composite metasurface

“…In the figure, the left part indicates the WTPR composed of a chiral metasurface structure with patterned metallic films on both sides of a dielectric substrate, and the right part is the metasurface absorber which is made of a resistance loaded metallic cut-wire on top of a dielectric substrate connecting through two conducting via holes to the metallic wire at the backside. The WTPR is transmissive over a wide band with a polarization rotation window at one particular frequency, which is contrast to previous works [6][7][8][9][10][11][12][13][14][15][16][17][18] that are transmissive only around the polarization rotation frequency. The metasurface absorber whose operation band covers the SWTA's is absorptive for the incident polarization but transmissive for the cross polarization.…”

“…Besides, almost the cross-polarization convertors studied in Ref. [6][7][8][9][10][11][12][13][14][15][16][17][18] are completely reflective outside of the cross-polarization conversion band.…”

“…We select a particular design of the polarization rotator through the T matrix analysis that could achieve high wave transmission outside the polarization rotation band rather than reflective in traditional designs. [6][7][8][9][10][11][12][13][14][15][16][17][18] Secondly, we design a novel polarization dependent metasurface absorber composed of unit cells with electric dipole, magnetic loop and loading resistance. Finally, an SWTA is realized with composite metasurface of the WTPR and a polarization dependent absorber.…”

“…[6][7][8] However, the structures are very sensitive to the polarization of the incident wave. The introduction of chiral metamaterials (CMMs) [9][10][11][12][13][14][15][16][17][18] has provided an alternative approach for realizing polarization rotators or convertors. A simple algorithm of bilayered CMMs utilizing transmission matrix (T matrix) provides a useful tool to analyze EM wave response of complex CMMs, and it may serve as a guide to identifying designs for a desired polarization response.…”

Broadband reflective multi-polarization converter based on single-layer double-L-shaped metasurface

“…Polarization converter is a kind of polarization control device which can effectively change the polarization state of incident wave. Conventional methods to manipulate polarizations include using refractive index gradient materials [7], anisotropic and chiral metamaterials [8][9][10][11][12][13][14][15]. However, the polarization converters based on these materials generally have narrow operating bandwidth.…”