Atomic-scale photonic hybrids for mid-infrared and terahertz nanophotonics

Abstract

The field of nanophotonics focuses on the ability to confine light to nanoscale dimensions, typically much smaller than the wavelength of light. The goal is to develop light-based technologies that are impossible with traditional optics. Subdiffractional confinement can be achieved using either surface plasmon polaritons (SPPs) or surface phonon polaritons (SPhPs). SPPs can provide a gate-tunable, broad-bandwidth response, but suffer from high optical losses; whereas SPhPs offer a relatively low-loss, crystal-dependent optical response, but only over a narrow spectral range, with limited opportunities for active tunability. Here, motivated by the recent results from monolayer graphene and multilayer hexagonal boron nitride heterostructures, we discuss the potential of electromagnetic hybrids--materials incorporating mixtures of SPPs and SPhPs--for overcoming the limitations of the individual polaritons. Furthermore, we also propose a new type of atomic-scale hybrid--the crystalline hybrid--where mixtures of two or more atomic-scale (∼3 nm or less) polar dielectric materials lead to the creation of a new material resulting from hybridized optic phonon behaviour of the constituents, potentially allowing direct control over the dielectric function. These atomic-scale hybrids expand the toolkit of materials for mid-infrared to terahertz nanophotonics and could enable the creation of novel actively tunable, yet low-loss optics at the nanoscale.

Generalized 4 × 4 matrix formalism for light propagation in anisotropic stratified media: study of surface phonon polaritons in polar dielectric heterostructures

“…As the layer thicknesses d are further reduced, extreme optical confinement λ/d > 1000 may be achieved which is typically inaccessible in plasmonics due to the much shorter wavelengths employed 47 . In the ultimate regime of atomicscale heterostructures 25,26 , one can additionally expect the optical properties to deviate from calculations using bulk parameters of the constituent materials due to microscopic modification of the material properties 25 . As we have shown, the formalism presented here is perfectly suited to simulate the optical response of such systems and could therefore be very useful in future studies of ultrathin-film dielectric heterostructures.…”

“…Here, the highly dispersive and often strongly anisotropic behavior of the dielectric function precludes the use of formalisms that are restricted to special cases. However, it is exactly in these materials and atomic-scale heterostructures thereof [23][24][25][26] , that SPhPs have very recently been demonstrated to enable many novel phenomena such as hyperbolic superlensing 27,28 and negative refraction 29,30 . For instance, hexagonal boron nitride as one of the key components of van der Waals heterostructures 31 , displays many interesting nanophotonic properties due to its naturally hyperbolic character 23,28,30,32,33 .…”

Dyakonov surface waves at the interface between hexagonal-boron-nitride and isotropic material

“…As presented in the previous section, the propagation of DSWs at the dielectric-elliptic interface could be theoretically described via Eqs. (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). In this section we present the results from theoretical calculation.…”

Large Photothermal Effect in Sub‐40 nm h‐BN Nanostructures Patterned Via High‐Resolution Ion Beam

“…Thus, significant effort over the past decade has focused on creating nanostructures and nanoscale devices from 2D crystals such as graphene that can manipulate their excellent optoelectronic, thermal, and mechanical properties. There has also been recent work in creating van der Waals (vdW) heterostructures composed of graphene, hexagonal boron nitride (h‐BN), and other 2D materials with hybrid properties beyond those that can be achieved using a single type of 2D crystal. For this reason, h‐BN has emerged as an invaluable material because it is an ideal substrate for preserving the intrinsic properties of 2D materials and nanotubes .…”