good evening all meep user. I try to compute transmission and reflection in photonic crystal. I attach my ctl file here. This is 2D photonic crystal with hexagonal lattice. It has 9 rows wtih each row consists of 30 or 31 cylinder with dielctric index 12.96 --------------------------------------------------------------------------------------------------------- (define notomi (make dielectric (index 12.96)))
(define awal (/ (sqrt 3) -2))
(set! geometry-lattice (make lattice (size 40 24 no-size)))
(set! default-material air) ; everything is airl
(define-param kdir (vector3 1 1))
(define-param active false)
(define-param r 0.35)
(define-param N1y 4)
(define-param N1x 30)
(define-param N2y 3)
(define-param N2x 29)
(define-param no-thing? false) ; if true, have straight waveguide, not bend
(set! geometry
(append
(geometric-objects-duplicates (vector3 0 (sqrt 3) 0) 0 N1y
(geometric-objects-duplicates (vector3 1 0 0) 0 N1x
(list
(make cylinder (center -14.5 (* -2
(sqrt 3)) 0) (radius r) (height infinity)
(material notomi)))))
(geometric-objects-duplicates (vector3 0 (sqrt 3) 0) 0 N2y
(geometric-objects-duplicates (vector3 1 0 0) 0 N2x
(list
(make cylinder (center -14 (+ (* -1
(sqrt 3)) awal) 0) (radius r) (height infinity)
(material notomi)))))
)
)
(set! pml-layers (list (make pml (thickness 1.0))))
(set! resolution 20)
(define-param fcen 1) ; pulse center frequency
(define-param df 0.5) ; pulse width (in frequency)
(set! sources (list
(make source
(src (make gaussian-src (frequency fcen) (fwidth df)))
(component Ez) (amplitude 10)
(center 0 -5))))
(define-param nfreq 1000) ; number of frequencies at which to compute flux
(define trans1 ;
(add-flux fcen df nfreq
(make flux-region
(center 0 0) (size 32 0))))
(define trans2 ;
(add-flux fcen df nfreq
(make flux-region
(center 0 3.8) (size 32 0))))
(define refl ; reflected flux
(add-flux fcen df nfreq
(make flux-region
(center 0 -3) (size 32 0))))
;(define-param compute-mode? false)
(run-sources+ (stop-when-fields-decayed
50 Ey
(vector3 0 3.5 0)
1e-3)
(at-beginning output-epsilon)
(during-sources
(in-volume (volume (center 0 0) (size 0 24))
(to-appended "ez" (at-every 0.5 output-efield-z)))))
(display-fluxes trans1 trans2 refl)
---------------------------------------------------------------------------------
As reference, I do computation without structure. I do this by set structure
like this
-------------------------------------------------------------------
(set! geometry
)
---------------------------------------------------------------------
My problem is the result shows number larger then 1, at frequency near 0. And
at other frequency, the number is too low. I do not see any peakse as the sign
of existence of transmission band and band gap.
I hope some one can help me about this and give some helps. Thank you for the
help.
With regard
Andika Asyuda
---------------------------------
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slab2_s.ctl
Description: 821142768-slab2_s.ctl
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