A Near-Infrared Multi-Band Perfect Absorber Based on 1D Gold Grating Fabry-Perot Structure

Abstract

In recent years, multi-band perfect absorbers have great advantages in spectroscopy, infrared detection and other fields. Here we propose and use the finite-difference time-domain (FDTD) method to numerically calculate the multi-band absorber based on 1D gold grating Fabry-Perot (FP) structure. The full-wave simulation results show that under normal incident conditions, four different absorption peaks can be obtained in the near-infrared band and the absorption is all close to 1. These resonance peaks are derived from the third-, fourth-, fifth-, and sixth-order resonances of mode coupling in the FP cavity, respectively. The narrowest absorption bandwidth is 24 nm and the quality factor is 37.6. By adjusting the structural parameters of the grating, its spectrum can be adjusted and selected, and its working angle tolerance can reach 50 •. In addition, numerical results show that the absorber can detect slight changes in the environment when used as a sensor. Therefore, our absorber has potential applications in the field of sensor detection.

Graphene-Based Multiband Chiral Metamaterial Absorbers Comprised of Square Split-Ring Resonator Arrays With Different Numbers of Gaps, and Their Equivalent Circuit Model

“…There is a need for multi-band chiral absorbers in THz communication systems [15] when necessary to absorb more information through multibands. Similar needs of multi-band absorbers are in sensing [16,17], spectroscopy, and imaging [18] applications. However, most of the published chiral metamaterial absorbers are not graphenebased resonators, so their absorption spectra and chirality responses are not dynamically tunable.…”

All-Dielectric Phase-Gradient Metasurface Performing High-Efficiency Anomalous Transmission in the Near-Infrared Region

“…For the metasurface we propose in this work, since the structural parameters of each element are in the range of 100 to 220 nm, as shown in Table 1 , no Mie resonances are excited within this range. Therefore, we can assume that the phase shift is mainly based on the Fabry–Pérot resonance [ 6 , 39 , 40 , 42 ]. According to the generalized Snell’s law, anomalous transmission can be achieved if a metasurface has a phase shift ability.…”

All-dielectric Phase-gradient Metasurface Performing High-efficiency Anomalous Transmission in the Near-infrared Region

“…It requires the nanorods to be high enough to form resonance condition for phase shift, which also explains the phenomenon shown in Fig. 2(a) [6,38,39]. According to the generalized Snell law, anoma- lous transmission can be achieved if a metasurface has a 2π phase shift ability.…”