Ricerc@Sapienza

We report on the extrinsic chirality behavior of GaAs-based NWs asymmetrically
hybridized with Au. The samples are fabricated by a recently developed,
lithography-free self-organized GaAs growth, with the addition of AlGaAs shell and
GaAs supershell. The angled Au flux is then used to cover three-out-of-six sidewalls
with a thin layer of Au. Oblique incidence and proper sample orientation can lead
to circular dichroism. We characterize this chiral behavior at 532 nm and 980 nm
by means of photo-acoustic spectroscopy, which directly measures the difference in
absorption for the circularly polarized light of the opposite headedness. For the first
time to our knowledge, circular dichroism is observed in both the amplitude and the
phase of the photo-acoustic signal. We strongly believe that such samples can be
used for chiral applications, spanning from circularly polarized light emission, to the
enantioselectivity applications.