Broadband Perfect Optical Absorption by Coupled Semiconductor Resonator-Based All-Dielectric Metasurface

Abstract

Resonance absorption mechanism-based metasurface absorbers can realize perfect optical absorption. Further, all-dielectric metasurface absorbers have more extensive applicability than metasurface absorbers that contain metal components. However, the absorption peaks of the all-dielectric metasurface absorbers reported to date are very sharp. In this work, we propose a broadband optical absorption all-dielectric metasurface, where a unit cell of this metasurface is composed of two coupled subwavelength semiconductor resonators arrayed in the direction of the wave vector and embedded in a low-index material. The results indicate that the peak absorption for more than 99% is achieved across a 60 nm bandwidth in the short-wavelength infrared region. This absorption bandwidth is three times that of a metasurface based on the conventional design scheme that consists of only a single layer of semiconductor resonators. Additionally, the coupled semiconductor resonator-based all-dielectric metasurface shows robust perfect absorption properties when the geometrical and material parameters—including the diameter, height, permittivity, and loss tangent of the resonator and the vertical and horizontal distances between the two centers of the coupled resonators—are varied over a wide range. With the convenience of use of existing semiconductor technologies in micro/nano-processing of the surface, this proposed broadband absorption all-dielectric metasurface offers a path toward realizing potential applications in numerous optical devices.

Anti-reflecting metasurface for broadband polarization independent absorption at Ku band frequencies

“…MMA is widely used in the microwave regime for various applications such as in micro-bolometers, anechoic chamber, scattering reductions 31 , thermal sensing 32 , and in energy harvesting 33 . Recently, perfect absorbers operating at infrared frequencies are designed using all dielectric semiconductor materials 34 . The design consists of semiconductor resonators positioned in the direction of wave vector meanwhile embedded in low refractive index medium.…”

Germanium Metasurfaces with Lattice Kerker Effect in Near-Infrared Photodetectors

“…The simulation results indicate that the Kerker condition is satisfied when the transverse period, P y , is 940 nm, and the reflectance is suppressed. In nanoparticles with a small imaginary part of the refractive index (referred here as low- k ), the energy of backward scattering can be transferred to forward scattering, which means that the transmittance is increased. , However, for nanoparticles with a large imaginary part of the refractive index (referred to here as high- k ), the energy of forward scattering can be stored inside the particles, resulting in a low transmittance of light through the structure. − Ge has a moderate imaginary part of the refractive index at 1550 nm, which is sufficient to create the narrowband absorptance. The material loss affects the backward scattering transferred to forward scattering or stored inside (becoming absorptance), as proposed in our previous work …”

Switchable multifunctional metasurface with broadband absorption and polarization conversion in the terahertz frequency band

“…Metasurface refers to artificially designed subwavelength structures, mainly composed of media and metals, whose structural dimensions are much smaller than the operating wavelength. Because metasurface can be used to adjust the amplitude, 4 phase, 5 and polarization 6 states of electromagnetic waves, it is widely used in stealth cloaks, 7 radar antennas, 8 super lenses, 9 and absorbers 10 …”

“…Because metasurface can be used to adjust the amplitude, 4 phase, 5 and polarization 6 states of electromagnetic waves, it is widely used in stealth cloaks, 7 radar antennas, 8 super lenses, 9 and absorbers. 10 Compared with the traditional absorber, the absorber based on metasurface has the characteristics of strong absorption, thin thickness, and light weight. Since Landy et al 11 designed a metasurface-based open ring perfect absorber in 2008, various types of absorbers have come into being, such as narrowband absorption, 12 broadband absorption, 13 and multiband absorption.…”