Hybrid indium tin oxide-Au metamaterial as a multiband bi-functional light absorber in the visible and near-infrared ranges

Abstract

Metamaterial nearly perfect light absorbers (MPAs) with dual-narrowband functionality—that absorb light in two narrowband adjacent wavelength regions—have attracted considerable attention due to their intriguing applications, such as sensing, photovoltaic, and thermal emission. Here, we propose a multi-band MPA with two narrowband absorption responses that are centered on the visible and near-infrared (NIR) wavelengths (773 nm and 900 nm, respectively) and a broadband absorptive characteristic in another window in the NIR region (ranging from 1530 nm to 2700 nm with a bandwidth of 1170 nm). The MPA comprises a periodic array of self-aligned hybrid indium tin oxide (ITO)-Au split-ring-resonators that are separated from an optically thick bottom reflector with a SiO2 layer. Based on numerical calculations, which are accompanied with a semi-analytical examination, we find that the dual narrowband and broadband responses are attributed to the hybridization of the optical responses of gold as a plasmonic material with the ones of ITO. Note that ITO acts as a low-loss dielectric in the visible range and a lossy plasmonic material in the NIR region. Moreover, due to the applied symmetry in the unit cell of the metamaterial, the proposed MPA represents polarization insensitive and omnidirectional absorptive features. The proposed metastructure can find potential applications in selective thermophotovoltaic devices, thermal emitters, and sensors.

Epsilon-Near-Zero Metal Oxide-Based Spectrally Selective Reflectors

“…For comparison, a similar coating has been evaluated on a transparent substrate like glass. Design of ITO-based meta-surfaces, broadband absorbers, and spectrally selective absorbers and reflectors − has gained traction recently owing to material and processing advantages . Interestingly, the ∼500 nm thick multilayer coating of ITO/Cr/Cr 2 O 3 investigated here imparts the same spectral selectivity to both SS and glass, leveraging the ENZ properties of ITO.…”

Broadband plasmon-induced transparency to an anapole mode induced absorption conversion Janus metastructure by a waveguide structure in the terahertz region

“…Electronically induced transparency (EIT) is a quantum interference effect based on a three-energy atomic system, which is achieved by generating sharp transmission windows within a wide reflection or absorption band. It is expected to be useful in communication, 7 photonic storage, photonic conversion, 8 and high-sensitivity sensors. 9 Despite its usefulness, the practical applications of EIT have been limited by specific and stringent environmental requirements for atomic-quantum interference formation, which has hindered the miniaturization of EIT devices.…”

Broadband Plasmon‐Induced Transparency to a Electromagnetically Induced Absorption Conversion Metastructure Based on Germanium

“…[ 6–8 ] EIT is a highly resonant phenomenon that significantly slows down the incident electromagnetic wave velocity [ 9,10 ] while greatly exacerbating the dispersion variation in opaque media, resulting in a large group index (GI). [ 11 ] As an intrinsic quantum mechanical phenomenon accompanied by strong dispersion, EIT is expected to be useful in areas such as quantum switching, [ 12 ] photon storage, [ 13 ] four‐wave mixing, [ 14 ] and regulations in light‐pulse. [ 15 ] The research history of EIT has spanned a century, and the first real experimental phenomenon of EIT was observed in a three‐energy atomic system as early as 1991 by Boiler et al.…”

“…[11] DOI: 10.1002/andp. 202200425 As an intrinsic quantum mechanical phenomenon accompanied by strong dispersion, EIT is expected to be useful in areas such as quantum switching, [12] photon storage, [13] four-wave mixing, [14] and regulations in light-pulse. [15] The research history of EIT has spanned a century, and the first real experimental phenomenon of EIT was observed in a threeenergy atomic system as early as 1991 by Boiler et al [16] However, the harsh experimental environment required to realize EIT, such as ultra-low temperature [17] and high-intensity laser, [18] seriously hinders the miniaturization of EIT devices and their application in practical engineering.…”