Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An alternate way to obtain the aberration expansion in Helmholtz Optics   Exploiting the similarities between the Helmholtz wave equation and the
Klein-Gordon equation, the former is linearized using the Feschbach-Villars
procedure used for linearizing the Klein-Gordon equation. Then the
Foldy-Wouthuysen iterative diagonalization technique is applied to obtain a
Hamiltonian description for a system with varying refractive index. Besides
reproducing all the traditional quasiparaxial terms, this method leads to
additional terms, which are dependent on the wavelength, in the optical
Hamiltonian. This alternate prescription to obtain the aberration expansion is
applied to the axially symmetric graded index fiber. This results in the
wavelength-dependent modification of the paraxial behaviour and the aberration
coefficients. Explicit expression for the modified coefficients of the
aberration to third-order are presented. Sixth and eighth order Hamiltonians
are derived for this system.

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The categories of this paper are: funct-an
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph