Extreme Diffraction Management in Phase‐Corrected Gradient Metasurface by Fourier Harmonic Component Engineering

Abstract

Beam diffraction management with on-demand efficiency over compact devices is important in various applications, such as communications, spectroscopy, wireless power transfer, and others. Recently, the in-depth study of metasurfaces, such as phase gradient metasurfaces (PGMs) or metagratings (MGs) made of discrete elements, has promoted an ultrathin platform to manipulate diffractions. However, most studies only focus on symmetrical diffraction orders or different propagating diffraction orders with equally distributed energy. It is difficult to efficiently excite beams with arbitrary energy distribution by phase-only metasurfaces due to the complex optimization procedure. Here, to address these challenges, Fourier harmonic component engineering is proposed to allocate the energy between multiple diffraction beams. By introducing phase-corrected gradient (PCG) on the metasurface platform, lossless transformation from the incidence to far-field patterns can be obtained. A variety of diffraction situations are considered (symmetric and asymmetric, with equal or arbitrary energy ratio), where the simulated and measured far-field patterns are in excellent agreement with the theoretical predictions and the achieved diffraction efficiency is up to 98.3%. The proposed method paves the way for multichannel wireless communication applications and can be readily extended to other frequency regions.

A Simulation Study of the Dynamical Control of Optical Skyrmion Lattices through the Superposition of Optical Vortex Beams

“…According to the radius formula derived from the geometric relationship, the radius of 12 rings has a strict recursive relationship, and once the initial radius is changed, not only will the radius of the other 11 rings change, but the distance between the radius of the two adjacent rings also changes. Obviously, the recursive relationship is still satisfied mathematically, but the radius of adjacent rings changes significantly, and the transmission phase [24] π cannot be strictly maintained, which does not meet the requirements of our design. We initially set the initial radius to 10 µm, but we could not obtain the skyrmion lattice we wanted.…”

“…The simulations were recorded separately as S 3 , S 4 , S 5 , S 6 . The order of the single-ring band rotation for each sample was set, respectively, as Θ 3 , Θ 4 , Θ 5 , Θ 6 ; the distribution of the localized surface of each set of nanorectangular pores was carefully designed considering the transmission phase [24] π, each sample, and 100 rectangular pores, which were arranged according to the rotation order. The number of rings was odd and the number of corresponding rings was even, and the radius of the initial ring r 1 was 15.5 µm.…”

Design, optimization, and comparative analysis of wide-band polarization conversion along with dual coding sequences for RCS reduction

“…In recent years, metasurfaces, a type of two-dimensional metamaterial, have garnered significant attention. Their unique electromagnetic properties offer unparalleled opportunities for manipulation, making them of a special interest 7 – 10 . The advent of metasurfaces has paved the way for a new approach to controlling the characteristics of electromagnetic waves, including amplitude, phase, polarization, and propagation modes 11 – 14 .…”

Inverse designed WS2 planar chiral metasurface with geometric phase

“…Metasurfaces, which consist of ultrathin metallic or dielectric nanostructures with dimensions smaller than the wavelength of light, have gained attention for their ability to manipulate optical phase, amplitude, and polarization over the wavefront with subwavelength resolution [1][2][3][4][5]. They have found numerous applications, including ultra-thin meta-lenses [6][7][8], holograms [1,[9][10][11][12][13], and optical vortex beam generators [3,[14][15][16][17].…”