Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fast estimation of propagation constants in crossed gratings   Fourier-based modal methods are among the most effective numerical tools for
the accurate analysis of crossed gratings. However, leading to computationally
expensive eigenvalue equations significantly restricts their applicability,
particularly when large truncation orders are required. The resultant
eigenvalues are the longitudinal propagation constants of the grating and play
a key role in applying the boundary conditions, as well as in the convergence
and stability analyses. This paper aims to propose simple techniques for the
fast estimation of propagation constants in crossed gratings, predominantly
with no need to solve an eigenvalue equation. In particular, we show that for
regular optical gratings comprised of lossless dielectrics, nearly every
propagation constant appears on the main diagonal of the modal matrix.

26
The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga