66 research outputs found
A finite element contour integral method for computing the resonances of metallic grating structures with subwavelength holes
We consider the numerical computation of resonances for metallic grating
structures with dispersive media and small slit holes. The underlying
eigenvalue problem is nonlinear and the mathematical model is multiscale due to
the existence of several length scales in problem geometry and material
contrast. We discretize the partial differential equation model over the
truncated domain using the finite element method and develop a multi-step
contour integral eigensolver to compute the resonances. The eigensolver first
locates eigenvalues using a spectral indicator and then computes eigenvalues by
a subspace projection scheme. The proposed numerical method is robust and
scalable, and does not require initial guess as the iteration methods.
Numerical examples are presented to demonstrate its effectiveness.Comment: 21 pages and 27 figure
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