Theoretical design of eight‐band linear‐to‐circular converter in reflection and transmission modes based on self‐complementary metasurfaces

Abstract

Multiband linear‐to‐circular (LTC) metamaterial converters have promising applications in modern optical system. However, it is challenging to design a converter with conversion bands of more than four and the axial ratio of less than 3 dB due to the coupling interaction of different resonant structures in a unit cell. In this article, we demonstrate a broad class of self‐complementary THz infinite thin metasurfaces composed of supercells of fractal metal rectangular patches and holes dimers of spanning 1 THz octave in bandwidth, while still being highly efficient. The advantages of this converter are as follows. The device is theoretically nonthickness; the LTC polarization conversion can be achieved in both the reflected and transmitted fields; the phase difference between two orthogonal linear polarization components is theoretically 90° in any frequency. Therefore, an eight‐band LTC converter is achieved in reflection and transmission modes. This new nonthickness multiband device will demonstrate a major advance toward an LTC synthetic metasurface in the THz band.

Implementing a transmission line electrical circuit model in a complementary metamolecule waveguide

“…The CM-WG is a subwavelength waveguide that consists of an array of meta-atoms with complementary characteristics, SRR and CSRR, harmonically coupled with their nearest neighbors. In recent years, self-complementary structures [16,17] are used for the design of metasurfaces mainly for the manipulation of the polarization of incident EM waves [18]. In the case of the proposed metamolecule, the orientations of meta-atoms and the polarization of the incident EM field determine the induced electric/magnetic dipoles.…”

Multiband linear and circular polarization rotating metasurface based on multiple plasmonic resonances for C, X and K band applications

“…Many cross-polarization conversion metasurfaces, which rotate the plane of polarization by 90°, have been reported 19 – 28 . In addition to the microwave frequency regime 29 – 31 , the developments in fabrication technology have pushed the control over polarization to even smaller wavelengths such as terahertz 32 – 34 , infrared and visible 35 – 37 frequencies.…”

Departure from the Babinet principle in metasurfaces supported by subwavelength dielectric slabs

“…Since under certain circumstances metasurfaces are realized by means of thin metals operating below the plasma frequency, and are hence essentially impenetrable patterned screens, the Babinet principle is a powerful tool for the designer, as it doubles the yield of a given design process [12] . In general, it may be useful to identify more efficient devices based on light scattering and generation in structured media [13][14][15][16][17] . Recent works have also provided generalization of the Babinet principle to partially coherent light [18] and finite-conductivity interfaces [19] , where it gives important guidelines towards the realization of frequency-independent screens, coherent perfect absorbers, polarization switches, integrated photonic components and terahertz reconfigurable filters [20][21][22][23][24][25] .…”