Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical chirality from dark-field illumination of planar plasmonic
  nanostructures   Dark-field illumination is shown to make planar chiral nanoparticle
arrangements exhibit circular dichroism in extinction analogous to true chiral
scatterers. Circular dichrosim is experimentally observed at the maximum
scattering of single oligomers consisting rotationally symmetric arrangements
of gold nanorods, with strong agreement to numerical simulation. A dipole model
is developed to show that this effect is caused by a difference in the
geometric projection of a nanorod onto the handed orientation of electric
fields created by a circularly polarized dark-field that is normally incident
on a glass substrate. Owing to this geometric origin, the wavelength of the
peak chiral response is also experimentally shown to shift depending on the
separation between nanoparticles. All presented oligomers have physical
dimensions less than the operating wavelength, and the applicable extension to
closely packed planar arrays of oligomers is demonstrated to amplify the
magnitude of circular dichroism. The realization of strong chirality in these
oligomers demonstrates a new path to engineer optical chirality from planar
devices using dark-field illumination.

30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas