Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Filamentation of ultrashort laser pulses in silica glass and KDP
  crystal: A comparative study   Ionizing 800-nm femtosecond laser pulses propagating in silica glass and in
potassium dihydrogen phosphate (KDP) crystal are investigated by means of a
unidirectional pulse propagation code. Filamentation in fused silica is
compared with the self-channeling of light in KDP accounting for the presence
of defect states and electron-hole dynamics. In KDP, laser pulses produce
intense filaments with higher clamping intensities up to 200 TW/cm$^2$ and
longer plasma channels with electron densities above $10^{16}$ cm$^{-3}$.
Despite these differences, the propagation dynamics in silica and KDP are
almost identical at equivalent ratios of input power over the critical power
for self-focusing.

14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex