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

Abstract

High field enhancement and near-perfect absorption in nanoantennas were realized by using in-plane (between nanoantenna arms), out-of-plane (between nanoantenna and reflector), and array coupling (between nanoantennas in an array); however, it was challenging to satisfy both conditions at the same time. In this paper, we show that a bowtie nanoantenna array integrated with an artificial impedance surface can simultaneously satisfy both high field enhancement and perfect absorption. The artificial impedance surface is implemented as a metallic patch array on a grounded 50 nm-thick SiO 2 substrate with reactive impedance surface (RIS) or high impedance surface (HIS) characteristic. Through the proposed design methodology, we designed a bowtie nanoantenna array on an optimum RIS patch array and achieved a high field enhancement factor (E/E 0) of 228 and a nearly perfect absorption rate of 98% at 230 THz. This novel design outperforms the previously reported nanoantenna structures and the same bowtie nanoantenna array designed using a conventional grounded SiO 2. We also show that the HIS-integrated bowtie antenna array cannot realize both goals at the same time because the highly reflective HIS cannot guarantee perfect absorption. The proposed RIS-combined nanoantenna array with high field enhancement and near-perfect absorption can be used for efficient infrared (IR) and optical detectors, sensors, and energy harvesting devices.

Computational modelling of light-matter interaction in aSi with CdSe/ZnS core/shell quantum dots and metal nanoantenna for solar cell applications

“…Since the Au NA was smaller than the incident EMW wavelength, the SPP was confined, resulting in a localised surface plasmon resonance (LSPR) effect. This effect boosted the oscillation of electron clouds within the Au NA, enhancing the optical absorption and local-field and reducing the EMW scattering [5,65,66]. Figure 6(a) shows the electric field by the non-gap aSiQDNASC model with the maximum value of 1.71 × 10 9 V nm −1 .…”

Surface-enhanced photoluminescence and Raman spectroscopy of single molecule confined in coupled Au bowtie nanoantenna

“…In the above plasmonic structure, the novel bowtie nanoantenna, composed of two metallic triangular plates, in particular is one of the most promising candidates for surface-enhanced photoluminescence spectroscopy since it can simultaneously enhance and confine electric field at sharp tips and tiny gaps. Meanwhile, bowtie structure fabricated using nanolithography in experiment is more tunable and reproducible compared to other dipole-like antenna designs [32][33][34]. Although bowtie nanoantenna have been widely used in the nanophotonics field [35][36][37], there are still many unresolved issues.…”