Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal emission by a subwavelength aperture   We calculate, by means of fluctuational electrodynamics, the thermal emission
of an aperture filled by vacuum or a material at temperature T. We show that
thermal emission is very different whether the aperture size is large or small
compared to the thermal wavelength. Subwavelength apertures filled with vacuum
(subwavelength blackbody) have their thermal emission strongly decreased
compared to classical blackbodies. A simple expression of their emissivity can
be calculated and their total emittance scales as T 8 instead of T 4 for large
apertures. Thermal emission of disk of materials with a size comparable to the
wavelength is also discussed. It is shown in particular that emissivity of such
a disk is increased when the material can support surface waves such as phonon
polaritons.

21
The categories of this paper are: adap-org
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th