  The capability to distinguish the handedness of circularly polarized light is
a well-known intrinsic property of a chiral nanostructure. It is a
long-standing controversial debate, however, whether a chiral object can also
sense the vorticity, or the orbital angular momentum (OAM), of a light field.
Since OAM is a non-local property, it seems rather counter-intuitive that a
point-like chiral object could be able to distinguish the sense of the
wave-front of light carrying OAM. Here, we show that a dipolar chiral
nanostructure is indeed capable of distinguishing the sign of the phase vortex
of the incoming light beam. To this end, we take advantage of the conversion of
the sign of OAM, carried by a linearly polarized Laguerre-Gaussian beam, into
the sign of optical chirality upon tight focusing. Our study provides for a
deeper insight into the discussion of chiral light-matter interactions and the
respective role of OAM.
