Enhanced light-matter interaction in an atomically thin semiconductor coupled with dielectric nano-antennas

Abstract

Unique structural and optical properties of atomically thin two-dimensional semiconducting transition metal dichalcogenides enable in principle their efficient coupling to photonic cavities having the optical mode volume close to or below the diffraction limit. Recently, it has become possible to make all-dielectric nano-cavities with reduced mode volumes and negligible non-radiative losses. Here, we realise low-loss high-refractive-index dielectric gallium phosphide (GaP) nano-antennas with small mode volumes coupled to atomic mono- and bilayers of WSe. We observe a photoluminescence enhancement exceeding 10 compared with WSe placed on planar GaP, and trace its origin to a combination of enhancement of the spontaneous emission rate, favourable modification of the photoluminescence directionality and enhanced optical excitation efficiency. A further effect of the coupling is observed in the photoluminescence polarisation dependence and in the Raman scattering signal enhancement exceeding 10. Our findings reveal dielectric nano-antennas as a promising platform for engineering light-matter coupling in two-dimensional semiconductors.

Enhanced Optical Emission from 2D InSe Bent onto Si‐Pillars

“…Optical resonances can occur when light interacts with sub‐wavelength dielectric cavities, as reported in WSe 2 layers coupled to dielectric nano‐antennas [ 42 ] and in vertical, small aspect‐ratio and subwavelength Si‐pillars. [ 43 ] The Q‐factor of the resonances depends on their morphology, geometry, and density.…”

Guide to optical spectroscopy of layered semiconductors

“…Optical spectroscopy also reveals magnetic proximity effects and charge transfer as non-magnetic and magnetic layers are placed in direct contact to form heterostructures [8][9][10] . For applications in photonics, such techniques reveal how light-matter coupling is enhanced when layered materials are placed in optical cavities or on resonators 11,12 . Optical spectroscopy can be used as a non-invasive technique for studying lattice structure, interlayer coupling and stacking that complements direct atomic-resolution imaging from electron microscopy [13][14][15][16][17] .…”

Facile Resist‐Free Nanopatterning of Monolayers of MoS2 by Focused Ion‐Beam Milling

“…Coupling to extended emitters or spatially extended ensembles of emitters usually leads to averaging effects, thereby hampering the observation of effects like emission enhancement, directional or polarization-controlled emission, valley routing, or strong coupling. [24,[26][27][28] Thus, a method to spatially confine the PL or SHG emission of TMD-MLs in hybrid photonic nanostructures to desired locations is highly desirable. To this end, strategies to remove or deactivate the TMD-ML emission locally in unwanted areas with nanoscale resolution, while preserving their unique photonic properties, including the strong excitonic PL and valley polarization in the remaining areas, are required.…”