Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Amplified short-wavelength light scattered by relativistic electrons in
  the laser-induced optical lattice   The scheme of the XUV/X-ray free electron laser based on the optical
undulator created by two overlapped transverse laser beams is analyzed. A
kinetic theoretical description and an ad hoc numerical model are developed to
account for the finite energy spread, angular divergence and the spectral
properties of the electron beam in the optical lattice. The theoretical
findings are compared to the results of the one- and three-dimensional
numerical modeling with the spectral free electron laser code PLARES.

35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci