Broadband anomalous reflective metasurface for complementary conversion of arbitrary incident polarization angles

Abstract

The abrupt phase changes at the interface can modulate the polarization and wavefront of electromagnetic waves, which is the physical mechanism of the plasmonic metasurfaces. Conventional polarization converters are difficult to obtain pure polarized light, and most of the anomalously reflecting metasurfaces are limited by the specific angle of incident polarization. Here, we present a high-efficient polarization-independent metasurface for broadband polarization conversion and anomalous reflection when a plane wave with an arbitrary polarization angle is incident vertically. We vary the dimensions of the polarization conversion unit cells and arrange them periodically to cover the full 2π phase range of cross-polarized light in two orthogonal directions. The simulation results show that the pure anomalous cross-polarization efficiency is over 80% over a wavelength range from 1400nm to 1800nm. In particular, the metasurface can realize the complementary conversion of polarization angle for incident light at any polarization angle, and deflect it to a specific angle. Our design provides strategies for miniaturization and integration of polarization conversion devices and systems.

Equivalent Circuit Models of a Bifunctional Optical Metasurface for Beam Splitting and Refractive Index Sensing

“…We assume that the electromagnetic wave travels back and forth in a unit, which can be seen as a Fabry− Peŕot cavity to produce standing waves with similar electromagnetic distributions and interference orders. The cavity is composed of a parallel-plate capacitor (Figure 7a), so we replace the role of RA with the capacitance C RA (8) where we stipulate that d x = d y = d z = P x . The C RA and NBPF are connected in series as a branch in the ECM, and the equivalent impedance Z SLR is calculated by paralleling three branches (9) Alike, we still take the Z SLR as the load of the transmission line to complete the establishment of the final ECM, as shown in Figure 7b.…”

“…Recently, metasurfaces have emerged as a well-established research hotspot in the micro/nano-optics field due to their unprecedented ability to control optical parameters, − such as amplitude, phase, and polarization . Compared with traditional three-dimensional metamaterials, the two-dimensional metasurface, composed of a single-layer meta-atom array, can not only avoid complex fabrication processes but also complete electromagnetic modulation within a subwavelength scale .…”

“…Recently, metasurfaces have emerged as a well-established research hotspot in the micro/nano-optics field due to their unprecedented ability to control optical parameters, 1−5 such as amplitude, 6 phase, 7 and polarization. 8 Compared with traditional three-dimensional metamaterials, the two-dimensional metasurface, composed of a single-layer meta-atom array, can not only avoid complex fabrication processes but also complete electromagnetic modulation within a subwavelength scale. 9 The design, analysis, and optimization of metasurfaces are mostly based on the classical electromagnetic theory; thus, the full-wave numerical simulation technology can provide precise optical responses from metasurfaces with arbitrary meta-atom structures and arrangements through solving Maxwell's equations.…”

Advanced Optical Imaging Based on Metasurfaces

“…[6,7,[57][58][59][60][61] Among them, metalenses that are specially designed for focusing and imaging are one of the most important categories of metasurface in practical applications. [13,18,59,[62][63][64][65][66][67][68][69][70][71][72] However, for metalens-based imaging, to obtain diffraction-limited focusing and high-resolution imaging, metalens needs to meet the following conditions: high numerical aperture, [65,66,70,[73][74] wide field of view, [75][76][77] no chromatic aberration, [52,78] monochromatic aberration, [79][80][81][82][83][84] etc. Numerous efforts are now being made to achieve subwavelength high-resolution imaging based on metasurface.…”