Hi All,
I'm going nuts here. It's most probably due to me or my lack of
knowledge of the MPB package. But anyway, your help it highly appreciated.
I'm trying to calculate the dispersion relation of a narrow type of W1
waveguide. The width of such a waveguide is not a single row of hole
missing in a triangular lattice, but more narrow. This means for the MPB
script, that I cannot use the duplicate-objects-over-lattice function,
but I decided to do it by hand, so I have the additional flexibility of
tuning the hole radii individually. Anyway.
Take a look at the attached image, or run the script and look at the
geometry. The outer most cilinder is somehow truncated, and if I try to
place an object even further away from the center, it doesn't appear at
all. Is this a bug, or is it me?
Anyone? Thanks in advance.
greets, Rob Engelen
AMOLF
-----------------------------------------
(define-param supercell-y 12.7916) ; the (odd) number of lateral
supercell periods
(set! geometry-lattice (make lattice
(basis1 (/ (sqrt 3) 2) -0.5)
(basis2 (/ (sqrt 3) 2) 0.5)
(size 1 supercell-y no-size)))
(define-param eps 8.17045) ;
(define-param r0 0.3);
(define-param r1 0.1);
(define-param r2 0.2);
(set! geometry (list
(make block (center 0) (size infinity infinity infinity)
(material (make dielectric(epsilon eps))))
(make cylinder (center -0.1042 -0.7916 0) (radius r1) (height
infinity) (material air))
(make cylinder (center 0.8958 -1.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center 0.8958 -2.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center 1.8958 -3.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center 1.8958 -4.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center 2.8958 -5.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center 0.1042 0.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center -0.8958 1.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center -0.8958 2.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center -1.8958 3.7916 0) (radius r2) (height
infinity) (material air))
; (make cylinder (center -1.8958 4.7916 0) (radius r2) (height
infinity) (material air))
(make cylinder (center 1.2 -3.2 0) (radius .5) (height infinity)
(material air))))
(set-param! resolution 32)
(run-te)
-------------------------------------------
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