3D-printed chiral metasurface as a dichroic dual-band polarization converter

Abstract

We propose a novel design of a true 3D chiral metasurface behaving as a spatial polarization converter with asymmetric transmission. The metasurface is made of a lattice of metallic sesquialteral (one and a half pitch) helical particles. Each particle contains six rectangular bars arranged in a series one above the another creating a spiral. The proposed metasurface exhibits a dual-band asymmetric transmission accompanied by the effect of a complete polarization conversion in the response on the particular distributions of currents induced in the particle's bars by an incident wave. Regarding circularly polarized waves the metasurface demonstrates a strong circular dichroism. A prototype of the metasurface is manufactured for the microwave experiment by using 3D-printing technique utilizing Cobalt-Chromium alloy, which exhibits good performances against thermal fatigue and corrosion at high temperatures. Our work paves the way to find an industrial solution on fabricating communication components with efficient polarization conversion for extreme environments.

Chiral metasurfaces formed by 3D-printed square helices: A flexible tool to manipulate wave polarization

“…In the present paper, we extend the result of our letter Ref. 40 and present a systematic study of a true 3D chiral metasurface whose particles are constructed from the rectangular bars stacked together in a multilayered fashion to form chiral helices. First, we develop an efficient theoretical method that allows us to calculate transmission characteristics of a multilayered structure in the form of double-periodic slabs.…”

“…This is because the helical particles with even number of bars are symmetric with respect to the orthogonal linearly polarized waves normally incident on opposite sides of the structure (see also results of Ref. 40 for the distribution of polarization currents flowing along the bars at the resonant frequencies). Contrary to T xx and T yy , the cross-polarization transmission coefficients T yx and T xy of x-and y-polarized waves are dissimilar.…”

Chiral-selective Plasmonic Metasurface Absorber Based on Bilayer Fourfold Twisted Semicircle Nanostructure at Optical Frequency

“…The chiral-selective absorption or transmission difference between the LCP and RCP lights can be characterized by CD parameter Δ. Figure 3(a) presents the CD spectrum of the PMSA, where the main peaks of CD parameter are about 0.85 and 0.91 at two selectively resonance frequencies, respectively; which is much greater than the current reported chiral nanostructures [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][34][35][36][37][38][39][40]. The giant CD effect is caused by the strong chirality of the PMSA.…”

“…CMSs have gained tremendous interest since it can exhibit exotic EM properties including negative refractive index and optical activity [8,9], asymmetric transmission [10,11], giant CD effect [12][13][14], polarization conversion [15,16], and wave front manipulation [17,18]. Since then, various CMSs structures (such as split-ring, gammadion, spiral wire, L-shaped and so on) have been designed to achieve highly-e cient selective chiral eld enhancement for LCP or RCP light as well as CD effect [19][20][21][22][23][24][25][26][27][28][29][30].…”

A General Recipe for Nondispersive Optical Activity in Bilayer Chiral Metamaterials

“…In recent years, significant efforts have been devoted to the realization of metamaterials with strong chirality due to their potential exotic physics, such as negative refraction, negative reflection, asymmetric transmission, repulsive Casimir force, tunable optical chirality, nonlinear chiroptical responses, ultrasensitive enantiomer differentiation, topologically protected photonic surface states, and circularly polarized light detection . Although it is not mentioned above, chiral metamaterials basically exhibit gigantic optical activity and circular dichroism, the potential of which can be clearly seen in the realization of compact polarization rotators, and circular polarizers .…”