Perfect Absorption Efficiency Circular Nanodisk Array Integrated with a Reactive Impedance Surface with High Field Enhancement

Abstract

Infrared (IR) absorbers based on a metal–insulator–metal (MIM) have been widely investigated due to their high absorption performance and simple structure. However, MIM absorbers based on ultrathin spacers suffer from low field enhancement. In this study, we propose a new MIM absorber structure to overcome this drawback. The proposed absorber utilizes a reactive impedance surface (RIS) to boost field enhancement without an ultrathin spacer and maintains near-perfect absorption by impedance matching with the vacuum. The RIS is a metallic patch array on a grounded dielectric substrate that can change its surface impedance, unlike conventional metallic reflectors. The final circular nanodisk array mounted on the optimum RIS offers an electric field enhancement factor of 180 with nearly perfect absorption of 98% at 230 THz. The proposed absorber exhibits robust performance even with a change in polarization of the incident wave. The RIS-integrated MIM absorber can be used to enhance the sensitivity of a local surface plasmon resonance (LSPR) sensor and surface-enhanced IR spectroscopy.

Theoretical Study of Localized Electric Field Enhancement for Plasmonic Nano-Imaging via Graphene-Based Heterogeneous U-Shaped Multi-Nanogaps Superlens

“…Where 'ng,2D' is the carrier concentration in the two dimensional graphene material, 'vF' is the Fermi velocity (≈1×10 6 m/s), and 'kF' is the Fermi wave vector. Moreover, this is the simple motive of graphene material for optical characteristics, enormous carrier mobility and interband transitions [22,23].…”

Tailoring cavity coupled plasmonic substrates for SERS applications

“…Cesario et al have validated a structure for controlling the scattering of incident light by coupling the plasmonic nanoparticles with a metallic mirror separated using a dielectric cavity [48]. It has been demonstrated that, excitation and coupling of localized surface plasmon supported by the nanoparticle and propagating surface plasmon supported by the film result in a multiple resonance response [43,49,50]. Various groups have investigated the effect of enhancing the absorption by these cavity-coupled structures for realizing plasmonic perfect absorbers [38,43,44,[49][50][51][52].…”

“…It has been demonstrated that, excitation and coupling of localized surface plasmon supported by the nanoparticle and propagating surface plasmon supported by the film result in a multiple resonance response [43,49,50]. Various groups have investigated the effect of enhancing the absorption by these cavity-coupled structures for realizing plasmonic perfect absorbers [38,43,44,[49][50][51][52]. Broadly two different approaches are employed for realizing perfect absorbers.…”

Bowtie Nanoantenna Array Integrated With Artificial Impedance Surfaces for Realizing High Field Enhancement and Perfect Absorption Simultaneously

“…Meanwhile, the RIS can improve antenna impedance matching by offsetting the capacitive near-field characteristic of the antenna through its inductive surface impedance characteristic [41]- [43]. Recently, the RIS was utilized in a MIM (metalinsulator-metal) absorber design in the near-IR range and the structure showed the increase of field enhancement along with nearly perfect absorption due to the impedance matching between the structure and the vacuum [44]. In our study, we applied both HIS and RIS to bowtie nanoantenna design to achieve the maximum field enhancement and perfect absorption at the same time.…”