Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extraordinary transmission through a single coaxial aperture in a thin
  metal film   We investigate experimentally the transmission properties of single
sub-wavelength coaxial apertures in thin metal films (t = 110 nm). Enhanced
transmission through a single sub-wavelength coaxial aperture illuminated with
a strongly focused radially polarized light beam is reported. In our
experiments we achieved up to four times enhanced transmission through a single
coaxial aperture as compared to a (hollow) circular aperture with the same
outer diameter.We attribute this enhancement of transmission to the excitation
of a TEM-mode for illumination with radially polarized light inside the single
coaxial aperture. A strong polarization contrast is observed between the
transmission for radially and azimuthally polarized illumination. Furthermore,
the observed transmission through a single coaxial aperture can be strongly
reduced if surface plasmons are excited. The experimental results are in good
agreement with finite difference time domain (FDTD) simulations.

19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc