Extraordinary Optical Transmission by Hybrid Phonon-Plasmon Polaritons Using hBN Embedded in Plasmonic Nanoslits.

Shinpei Ogawa,Shoichiro Fukushima,Masaaki Shimatani

doi:10.3390/nano11061567

Shinpei Ogawa, Shoichiro Fukushima + Show 1 more

Open Access

https://doi.org/10.3390/nano11061567

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Journal: Nanomaterials	Publication Date: Jun 14, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Mitsubishi Electric (Japan)

Abstract

Hexagonal boron nitride (hBN) exhibits natural hyperbolic dispersion in the infrared (IR) wavelength spectrum. In particular, the hybridization of its hyperbolic phonon polaritons (HPPs) and surface plasmon resonances (SPRs) induced by metallic nanostructures is expected to serve as a new platform for novel light manipulation. In this study, the transmission properties of embedded hBN in metallic one-dimensional (1D) nanoslits were theoretically investigated using a rigorous coupled wave analysis method. Extraordinary optical transmission (EOT) was observed in the type-II Reststrahlen band, which was attributed to the hybridization of HPPs in hBN and SPRs in 1D nanoslits. The calculated electric field distributions indicated that the unique Fabry–Pérot-like resonance was induced by the hybridization of HPPs and SPRs in an embedded hBN cavity. The trajectory of the confined light was a zigzag owing to the hyperbolicity of hBN, and its resonance number depended primarily on the aspect ratio of the 1D nanoslit. Such an EOT is also independent of the slit width and incident angle of light. These findings can not only assist in the development of improved strategies for the extreme confinement of IR light but may also be applied to ultrathin optical filters, advanced photodetectors, and optical devices.

Highlights

Cavity (Figure 6d) owing to the extremely small cavity size. These differences are likely to be related. These results confirm that Extraordinary optical transmission (EOT) occurs in the type-II RS band and is attributed to the Fabry–Pérot-like resonance induced by the hybridization of hyperbolic phonon polaritons (HPPs) in hexagonal boron nitride (hBN) and surface plasmon resonances (SPRs) in 1D nanoslits
EOT was produced in the type-II RS band of hBN, as well as in other wavelength regions
In wavelength regions other than the type-II RS band, EOT is attributed to conventional Fabry–Pérot-like resonance of SPRs in 1D nanoslits, where the EOT wavelength is proportional to the slit depth

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. HBN exhibits a natural hyperbolic dispersion relation in two infrared (IR) wavelength regions [9,10,11], the in-plane and out-of-plane permittivity in each region is significantly different and opposite in terms of their sign [10] This unique hyperbolic dispersion relation can enhance light–matter interactions, such as the extreme confinement of IR light [12,13] and hybridization of SPPs and HPPs [14,15,16,17]. The hybridization of surface plasmon resonances (SPRs) induced by metallic nanostructures and HPPs in hBN serves as a new platform for novel light manipulation Metallic nanostructures, such as 2D nanoholes and one-dimensional (1D) gratings, are well-known structures for implementing high-efficiency light control using SPPs, such as in extraordinary optical transmission (EOT) [38,39,40] and wavelength-selective perfect absorption/emission [41,42,43]. The remainder of this paper is arranged as follows: Section 2 presents the materials and calculation model used, Section 3 compares the transmittances of the 1D nanoslits using Si as the isotropic material and hBN as the anisotropic dielectric, and Section 4 concludes the paper

Material and Calculation Model

Isotropic Materials

Anisotropic hBN

Conclusions