Fig. 1.

Coupling of an atomically thin semiconductor to a dielectric nano-antenna. a Schematic view of a GaP dimer nano-antenna with a height $h$ = 200 nm, gap width g, and pillar radius r. b, c Calculated relative intensity ${\left(\mid E\mid ∕\mid E_0\mid \right)}^2$ of light at 685 nm scattered by a GaP dimer with $r$ = 50 nm, $h$ = 200 nm, and $g$ = 65 nm. $E$ ($E_0$) is the electric field amplitude of the light scattered by (normally incident on) the dimer. The polarisation of the incident light is shown with arrows. ${\left(\mid E\mid ∕\mid E_0\mid \right)}^2$ is calculated at the height of 200 nm corresponding to the top surface of the pillars. The inset shows the variation of ${\left(\mid E\mid ∕\mid E_0\mid \right)}^2$ along the horizontal and vertical dotted lines. d Atomic force microscopic (AFM) image of a GaP nano-antenna ($r=500$ nm) covered with a monolayer WSe${}_2$. e Simulated scattering ($Q_{\mathrm{scatt}}$) and absorption ($Q_{\mathrm{abs}}$) efficiency integrated over numerical aperture NA = 0.9 for a GaP nano-antenna ($g$ = 35 nm, $r$ = 100 nm) illuminated with a plane wave. Pink (red) dashed line $Q_{\mathrm{scatt}}$ for light scattered upwards in air (downwards into the substrate). Room temperature PL spectra are shown for 1L-WSe${}_2$ (orange) and 2L-WSe${}_2$ (purple). f Optical microscopic image showing PL from dimer nano-antennas array covered with 1L- and 2L-WSe${}_2$ illuminated with unpolarised white light (see ‘Methods’ for details). Scale bar is 10 μm. The yellow lines show the boundaries between 1L- and 2L-WSe${}_2$. PL from 1L (2L) sample shows as false yellow (purple) in the image. g Intensity profiles extracted from a dark-field (black) and PL (yellow) microscopic images for a dimer with $r$ = 500 nm measured along the dashed line in e. The intensity profiles are overlaid with the schematic of a dimer