Quantum Nanophotonics in Two-Dimensional Materials

Abstract

The field of 2D materials-based nanophotonics has been growing at a rapid pace, triggered by the ability to design nanophotonic systems with in-situ control 1 , unprecedented degrees of freedom, and to build material heterostructures from bottom up with atomic precision 2 . A wide palette of polaritonic classes [3][4][5][6] have been identified, comprising ultra-confined optical fields, even approaching characteristic length-scales of a single atom 7 . These advances have been a real boost for the emerging field of quantum nanophotonics, where the quantum mechanical nature of the electrons and/or polaritons and their interactions become relevant. Examples include, quantum nonlocal effects [8][9][10][11] , ultrastrong light-matter interactions [11][12][13][14][15][16] , Cherenkov radiation 13,17,18 , access to forbidden transitions 11 , hydrodynamic effects [19][20][21] , single-plasmon nonlinearities 22,23 , polaritonic quantization 24 , topological effects etc. 3,4 . In addition to these intrinsic quantum nanophotonic phenomena, the 2D material system can also be used as a sensitive probe for the quantum properties of the material that carries the nanophotonics modes, or quantum materials in its vicinity. Here, polaritons act as a probe for otherwise invisible excitations, e.g. in superconductors 25 , or as a new tool to monitor the existence of Berry curvature in topological materials and superlattice effects in twisted 2D materials.In this article, we present an overview of the emergent field of 2D-material quantum nanophotonics, and provide a future perspective on the prospects of both fundamental emergent phenomena and emergent quantum technologies, such as quantum sensing, single-photon sources and quantum emitters manipulation. We address four main implications (cf. Figure 1): i) quantum sensing, featuring polaritons to probe superconductivity and explore new electronic transport hydrodynamic behaviours, ii) quantum technologies harnessing single-photon generation, manipulation and detection using 2D materials, iii) polariton engineering with quantum materials enabled by twist angle and stacking order control in van der Waals heterostructures and iv) extreme light-matter interactions enabled by the strong confinement of light at atomic level by 2D materials, which provide new tools to manipulate light fields at the nano-scale (e.g., quantum chemistry 26 , nonlocal effects, high Purcell enhancement).

2D Boron Nitride Heterostructures: Recent Advances and Future Challenges

“…[ 8 ] Point defects, for instance, are the source of single‐photon emissions, and the discovery of this property has promoted the design of quantum emitters in a wide range of energies. [ 6,15 ]…”

Chip-Scale Quantum Emitters

“…Currently, as emerging materials for technological applications, two-dimensional (2D) compounds are able to play a critical role in the advancement of nanophotonics and quantum technology. In this way, a wide range of polaritonic states and ultraconfined optical fields can be used to build the quantum nanophotonics field, where the quantum mechanical nature of the electrons and polaritons and their interactions become relevant [63]. The intrinsic quantum nanophotonic phenomena, such as quantum nonlocal effects, ultrastrong light-matter interactions, Cherenkov radiation, polaritonic quantization, and topological effects that can be observed in 2D materials, provide an expectation of receiving new nanophotonics modes [63,64].…”

“…In this way, a wide range of polaritonic states and ultraconfined optical fields can be used to build the quantum nanophotonics field, where the quantum mechanical nature of the electrons and polaritons and their interactions become relevant [63]. The intrinsic quantum nanophotonic phenomena, such as quantum nonlocal effects, ultrastrong light-matter interactions, Cherenkov radiation, polaritonic quantization, and topological effects that can be observed in 2D materials, provide an expectation of receiving new nanophotonics modes [63,64]. A quantum emitter is one of the potential applications of 2D materials in a variety of quantum technologies and nanophotonics which are engineered by isolated color centers and quantum dots embedded in 2D materials [65].…”

Anisotropic Optical Response of WTe2 Single Crystals Studied by Ellipsometric Analysis

“…In the photonics field, 2D layered materials [ 19 , 20 ], and particularly the TMD family [ 21 ], offer many options for functional light control, strong light–matter interaction effects and reduced optical losses. We have to emphasize their notable optical anisotropy [ 22 , 23 ], which is a key factor in light manipulation due to the bi/trirefringence and di/trichroism effects [ 24 ], which result in spatial and polarization separation, enabling a virtually unlimited platform for the realization of the next generation (4G) of planar optics.…”