  The nonlinear process of second harmonic generation (SHG) in monolayer (1L)
transition metal dichalcogenides (TMD), like $WS_2$, strongly depends on the
polarization state of the excitation light. Combining plasmonic nanostructures
with $1L-WS_2$ by transferring it onto a plasmonic nanoantenna array, a hybrid
metasurface is realized impacting the polarization dependency of its SHG. Here,
we investigate how plasmonic dipole resonances affect the process of SHG in
plasmonic-TMD hybrid metasurfaces by nonlinear spectroscopy. We show, that the
polarization dependency is affected by the lattice structure of plasmonic
nanoantenna arrays as well as by the relative orientation between the $1L-WS_2$
and the individual plasmonic nanoantennas. In addition, such hybrid
metasurfaces show SHG in polarization states, where SHG is usually forbidden
for either $1L-WS_2$ or plasmonic nanoantennas. By comparing the SHG in these
channels with the SHG generated by the hybrid metasurface components, we detect
an enhancement of the SHG signal by a factor of more than 40. Meanwhile, an
attenuation of the SHG signal in usually allowed polarization states is
observed. Our study provides valuable insight into hybrid systems where
symmetries strongly affecting the SHG and open up the possibility for tailoring
the SHG in $1L-WS_2$ for future applications.
