  We investigate the plasmonic nanohelix as an individual subwavelength element
for locally probing light chirality. We show that an hybrid nanoantenna
combining a carbon-gold core-shell helix and a plasmonic nanoaperture transmits
circularly polarized light with the same handedness as the helix and blocks the
other. Such an assymmetric response is spatially localized, spectrally
broadband and background-free. Finally, we demonstrate the possibility to
engineer an individual plasmonic helix at the apex of a sharp tip typically
used in scanning near-field microscopies, thus opening the prospect of moveable
local probes for high resolution sensing and mapping of light chirality and
chiroptical forces
