Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intensity of parametric fluorescence pumped by ultrashort pulses   We investigate intensity of the parametric down conversion of ultrashort,
ultraviolet pulse both in a low- and high-conversion regime. In the first
regime, we develop a simple analytical expressions for the photon flux of the
fluorescence. Numerical simulations using three-dimensional stochastic Wigner
method provide results in the latter regime. We find that the perturbative
approximation for the photon flux as a function of the wavelength of the signal
and the observation angle, quantitatively describes even the non-perturbative
regime. For short pump pulses the intensity of the fluorescence is highest at
frequencies where the group velocities of the pump and the down-conversion are
equal. For longer pump pulses this requirement is gradually relaxed.
Additionally, for small pump beams, the intensity strongly depends on the
spatial divergence between interacting fields.

26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph