Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Singularity-driven Second and Third Harmonic Generation in a
  {\epsilon}-near-zero nanolayer   We show a new path to {\epsilon}~0 materials without resorting to metal-based
metamaterial composites. A medium that can be modeled using Lorentz oscillators
usually displays {\epsilon}=0 crossing points, e.g. {\epsilon}=0 at
{\lambda}~7{\mu}m and 20{\mu}m for SiO2 and CaF2, respectively. We show that a
Lorentz medium yields a singularity-driven enhancement of the electric field
followed by dramatic lowering of thresholds for a plethora of nonlinear optical
phenomena. We illustrate the remarkable enhancement of second and third
harmonic generation in a layer of {\epsilon}~0 material 20nm thick, and discuss
the role of nonlinear surface sources.

24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio