Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Organic near-infrared epsilon-near-zero materials with large optical
  nonlinearity   Epsilon-near-zero (ENZ) materials have shown great potential for nonlinear
optical applications, such as photon generation, all-optical switch, and time
refraction because of the ultrafast hot carriers and hot-carrier-induced
nonlinearity enhancement. Here, modified poly(3,4-ethylenedioxythiophene)
(PEDOT) films exhibit vanishing real permittivity near 1550nm, namely in the
conventional band (C band) for optical communications. For nonlinear refractive
index n_2 and absorption coefficient \alpha_2 without ENZ reinforcement, PEDOT
is 100 times larger than indium tin oxide (ITO), a kind of typical inorganic
ENZ material. The n_2 and {\alpha}_2 of modified PEDOT films at ENZ wavelengths
obtain a 22-fold enhancement due to ENZ-induced hot carrier redistribution
inside materials, compared to those at non-ENZ wavelengths. Pump-probe reveals
that hot holes in modified PEDOT (p-type) films exhibit a longer relaxation
time and a lower enhancement multiple of the carrier temperature than hot
electrons in n-type inorganic ENZ materials. Our findings firstly offer new
promising tunable organic ENZ materials with ENZ wavelengths in optical
communication bands and show unique properties of organic ENZ materials as
distinct from inorganic ENZ materials, which provide more possibilities for
on-chip nanophotonic devices, nonlinear optics, and plasmonics.

8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys