Dear MPB users I am studying the effect of the defect width of PC waveguide on dispersion curve. The CTL file is attached. first I erase three row of the holes in middle, and add two rows with a displacement in y direction. As you see the attached epsilon files for different displacement, you can see the rows are shifted in x direction as well.
1- why? can any body help? I did not shift rows in x direction! (as you see in
ctl file);
2-
as it is clear, the epsilon pictures are not triangular crystal any
more! shall I shift rows in -x direction to compensate the above
mentioned unwanted shift and let to study the effect of width only (not
affected by shift in x direction)?
Regards
Hassan
Part of CTL file
================
(define-param displacement-in+y-direction 1.25)
(define-param displacement-in-y-direction -1.25)
(set! geometry (list (make cylinder (center 0 0 0) (radius r)
(height infinity) (material air))))
(set! geometry
(append
(geometric-objects-lattice-duplicates geometry)
(list
;add a rod of epsilon on Center, to erase a row of rods and
form a waveguide:
(make cylinder (center 0 0 0) (radius r) (height infinity)
(material (make dielectric (epsilon eps)))
)
; add a rod of eps belowe, to fill a row of air
(make cylinder (center 0 1 0) (radius r) (height infinity)
(material (make dielectric (epsilon eps)))
)
; add a rod of eps above, to fill a row
(make cylinder (center 0 -1 0) (radius r) (height infinity)
(material (make dielectric (epsilon eps)))
)
; add a closer row above
(make cylinder (center 0 displacement-in-y-direction 0) (radius
r1) (height infinity)
(material air);(make dielectric (epsilon eps)))
)
; add a closer row belowe
(make cylinder (center 0 displacement-in+y-direction 0) (radius
r1) (height infinity)
(material air);(make dielectric (epsilon eps)))
)
)
)
)
==================
<<attachment: Epsilon after .25a shift.png>>
<<attachment: Epsilon-without shift.png>>
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