Dear Meep users,
I am trying to simulate the propagation of symmetric plasmonic mode in 2D MDM
waveguide. After few time units, the field seems to blow up for some unknown
reason. The next thing I did was to add some adequate loss to my metal and that
managed to contain things, at least so long as the simulation ran.
Is there still some issue with (lossless) dispersive metals extending into the
PML? I shall really appreciate if someone knowledgeable could clarify this
thing one way or the other as it would save me a lot of precious time. Below is
the code I am trying to run:
; code for simulating plasmonic mdm waveguide; parameter definition:
(define-param nm 1e-3)(define-param um 1) ; default unit is in micro meters
(define-param Lx (* 8 um)) ;Length of cell in x-direction(define-param Ly
(* 1 um)) ;Length of cell in y-direction(define-param Ldy (* 100 nm))
;Length of dielectric layer in y-direction(define-param dpml (* 400 nm))
;Width of pml layer(define-param dx 100) ;Spatial resolution
(define-param nd 2.2) ;index of dielectric(define-param omega_met
1e-15)(define-param sigma_met 39.32258e30)(define-param eps_met 1)(define-param
gamma_met 0) ;damping of Ag
(define-param H0 0.0833e6) ;source amplitude(define-param f0 0.67) ;source
frequency(define-param T 100) ;simulation run-time(define-param ramp (* 4 (/
1 f0))) ;ramp time(define-param dt 0.25) ;output sample
interval(define-param LSx (+ (* 1 nm) (/ Lx -2)) ) ;location of source
along x-axis(define-param LSy 0) ;location of source along y-axis
(set! default-material (make dielectric (epsilon 1) (E-polarizations (make
polarizability (omega omega_met) (gamma gamma_met) (sigma sigma_met))
)))
(set! geometry-lattice (make lattice (size (+ Lx (* 2 dpml)) (+ Ly (* 2 dpml))
no-size)))
(set! geometry (list (make block (center 0 0) (size (+ Lx (* 2 dpml)) Ldy
infinity) (material (make dielectric (index nd))))))
(set! sources (list (make source (src (make continuous-src (frequency f0)))
(width ramp) (component Hz) ;(amplitude H0) (center LSx LSy) (size 0 Ldy))))
(set! pml-layers (list (make pml (direction X) (thickness dpml))))
(set! resolution dx)
(use-output-directory)
(run-until T (at-beginning output-epsilon) (to-appended "lossless"
(at-every dt (in-volume (volume (center 0 0) (size Lx Ly))
output-hfield-z))))
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