  Due to their atomic layer thickness, direct bandgap, mechanical robustness
and other superior properties, transition metal dichalcogenides (TMDCs)
monolayers are considered as an attractive alternative to graphene for diverse
optoelectronic applications. Yet, due to the very nature of atomic layer
thickness, the interaction of light with TMDCs is limited, hindering overall
efficiency for optical applications. Therefore, in order for TMDCs to become a
true candidate as the material of choice for optoelectronics, there is a need
for a mechanism which significantly enhances the interaction of light with
TMDCs. In this paper, we demonstrate about 30-fold enhancement of the overall
photoluminescence emission intensity from a WS2 monolayer, by its coupling to a
hyperbolic metamaterial nanoantenna array. This enhancement corresponds to
nearly 300-fold enhancement per individual nanoantenna. This overall
enhancement is achieved by the combination of enhancing the excitation
(absorption) efficiency, alongside with enhancing the radiative decay rate. Our
result paves the way for the use of TMDCs in diverse optoelectronic
applications, ranging from light sources and photodetectors to saturated
absorbers and nonlinear media.
