Asymmetric transmission of linearly and circularly polarized waves in metamaterial due to symmetry-breaking

Abstract

A two-dimensional chiral structure with an h-shape and H-shape on opposing sides of a dielectric layer is proposed that can realize simultaneously dual-band asymmetric transmission of linearly and circularly polarized waves in the near-infrared band. Meanwhile, the structure realizes a maximum asymmetric transmission of 0.56 and 0.30 for linearly and circularly polarized waves, respectively, at the resonant frequency. These results have been analyzed with simulations in detail. The physical mechanism of linearly and circularly polarized wave transmission and conversion based on current distribution and electric fields is also investigated.

Multi-Band Asymmetric Transmission and 90° Polarization Rotator Based on Bi-Layered Metasurface with F-Shaped Structure

“…Figure 6g depicted the magnetic field profiles of the x-polarized wave at 8.7 and 10.4 GHz. We can clearly see that the in-phase (parallel) and out-phase (anti-parallel) modes have been excited [22]. The higher frequency modes of 10.4 GHz show obvious alignment of their magnetic dipole moments in out phase, which is similar to the current modes analyzed in Figs.…”

“…The asymmetric transmission (AT) for a certain polarization state can be defined as the difference between the transmittances in the two different propagation directions, which can be expressed as Δ lin x = |T yx | 2 − |T xy | 2 = − Δ lin y [22]. The numerical simulations and experimental results are shown in Fig.…”

“…Based on these structures, it is found that lack of symmetry plays an indispensable role in asymmetric transmission [9][10][11][12][13][14][15][16][17][18][19][20]. Recently, Menzel et al [21,22] proposed that a structure with a broken symmetry can realize dual-band asymmetric transmission of linearly and circularly polarized waves in optical regions, respectively, but the deficiency is that the asymmetric transmission for both polarized waves does not reach 0.6. Furthermore, Li et al [23] proposed that a structure consisting of an L-shaped metallic particle and a double nanoantenna realized broadband asymmetric transmission in the near-infrared regime.…”

“…In order to better understand the linearly polarized wave propagation in the chiral metamaterial, the T transmission matrix is introduced, which connects the generally complex amplitudes of the incident and the transmitted fields [22].…”

Broadband asymmetric light transmission through tapered metallic gratings at visible frequencies

“…Also, asymmetric transmission can be realized in different engineered material systems such as composite grating structures13141516171819, photonic crystals2021, metal-silicon waveguides22, and even in composition-graded semiconductor nanowires23. Recently, theoretical and experimental studies have proven that chiral metamaterials242526272829, hyperbolic metamaterials30 and all-dielectric digital metasurfaces3132 can enable asymmetric transmission for circularly and linearly polarized light2933. By judiciously engineering parameters of individual building blocks, such as geometry, size and material, metasurfaces are promising to replace conventional electromagnetic elements in nanophotonic devices3435.…”