Planar Broadband Huygens’ Metasurfaces for Wave Manipulations

Abstract

Cuesta, F. S.; Faniayeu, I. A.; Asadchy, V. S.; Tretyakov, S. A. Planar broadband Huygens' metasurfaces for wave manipulationsAbstract-Electrically thin and effectively two-dimensional material composites, metasurfaces, have been widely exploited for manipulation of electromagnetic waves. For many applications it is desired to transform incident waves of a specific frequency range keeping the metasurface invisible at other frequencies.Such frequency-selective response can be achieved based on subwavelength Huygens' inclusions. However, their fabrication requires sophisticated processes due to the three-dimensional geometry. Here, we propose a planar Huygens' meta-atom with the goal to open a way to realize broadband invisible metasurfaces with topologies suitable for the conventional printed circuit board fabrication technology. We synthesize and analyse, both numerically and experimentally, three different metasurfaces capable of polarization and amplitude transformations of incident waves.

Fabry-Pérot Huygens' metasurfaces: On homogenization of electrically thick composites

“…Eqs. (19) and (20) represent two equations in the two sets of unknowns n, n. They are generally solved by projecting each term in both equations into the Rayleigh basis e 2imx/d [46].…”

Achromatic Huygens’ Metalenses with Deeply Subwavelength Thickness

“…For this reason, previous works have utilized a metaatom con sisting of metallic chiral elements, where electric and mag netic responses naturally have the same resonant frequency, and can easily be made equal in the vicinity of this reso nance, yielding broadband transparency. [35,39,40] However, this approach does not allow easy control of the quality factor, as is required to engineer the groupdelay for broadband phase control. Unlike balanced chiral elements, the three cascaded metallic layer structure has electric and magnetic dipole moments which are not always equal, as a result of the dif ferent mechanisms by which they are induced.…”

Polarization Control with Helical Metasurfaces

“…x | at this wavelength. A single helix as a chiral inclusion has only axial dominant individual electric and magnetic dipole moments which can be balanced as [18][19][20]33]. Therefore, it requires at least two helices in the unit cell in order to achieve desired polarization conversions and simultaneous perfect impedance matching of the metasurface (zero reflection).…”

“…Huygens' metasurface based on chiral inclusions provides more opportunities in the controlling of the light polarization due to the well-defined and tailoring of the induced electric and magnetic dipole moments of chiral polarizable inclusions [12][13][14]. As a result, the orthogonal polarizations of linear polarized waves are manipulated independently in Huygens' chiral metasurface that leads to the near-perfect polarization conversion with the unit transmittance or reflectance, nonsplitting of the resonance, and broad transparency outside of the resonant band [15][16][17][18][19][20].…”