Dynamically tunable narrowband anisotropic total absorption in monolayer black phosphorus based on critical coupling

Abstract

A dynamically tunable anisotropic narrowband absorber based on monolayer black phosphorous (BP) is proposed in the terahertz (THz) band. The proposed absorber consists of a monolayer BP and a silicon (Si) grating, which is placed on a silica (SiO2) isolation layer and a gold (Au) substrate. The benefit from the critical coupling mechanism with guided resonance is the efficiency of the absorption can reach 99.9% in the armchair (AC) direction and the natural anisotropy of BP makes it only 87.2% in the zigzag (ZZ) direction. Numerical and theoretical studies show that the absorption efficiency of the structure is operatively controlled by critical coupling conditions, including the geometric parameters of the Si grating, the electron doping of BP and the angle of incident light, etc. More importantly, in the absence of plasmon response, this structure greatly enhances the interaction between light and matter in monolayer BP. In particular, there are several advantages in this structure, such as extremely high-efficiency absorption, excellent tunability, outstanding intrinsic anisotropy and easy manufacturing, which will show unusual and promising potential applications in the design of BP-based tunable high-performance devices.

Multiple poles resonances coupling with high sensitivity sensing for multiple bulging black phosphorus-based metasurface

“…BP relaxation rate η = 10 meV. Here, m ZZ and m AC are the effective mass for ZZ and AC directions as [37,38]…”

A tunable perfect absorber based on a black phosphorus/bowtie shaped cavity hybrid metasurface

“…24 The bandgap increases as the thickness of BP decreases, with a direct bandgap ranging from 0.3 to 2.0 eV, and it bridges the gap between the zero-bandgap graphene and the wide-gap TMDs. 25,26 BP can be used in electrostatic gating or chemical doping to adjust its carrier concentration, providing it with greater flexibility for optoelectronic applications. 27 The unique honeycomb hexagonal lattice of BP features a puckered surface with ridges, resulting in high in-plane anisotropy.…”

A Review: The Functional Materials-Assisted Terahertz Metamaterial Absorbers and Polarization Converters

“…Such changes can be applied to the entire spectrum region, but generally have a long response time [10][11][12][13][14]. The other method is to combine the metamaterial structures with the functional materials, including liquid crystals [15], black phosphorus [16,17], graphene [1], Dirac semimetal [18], phase change materials [19], and so on, treated as surrounding media or constituent materials. This method is to modulate the optical properties of the functional materials through external stimulation, thereby further realizing the dynamic control of metamaterials.…”