Dear All,
I'm a mpb user. I want to do some calculations about photonic crystal
fibers recently, especially the gap map and guided modes of pcfs.
I have searched a mpb code in this link:
http://www.mail-archive.com/mpb-discuss@ab-initio.mit.edu/msg00018.html
In this link, Steven metioned that "I've attached a couple of files I
used to compute gap maps for holey fibers. See in particular the use of the
"poly-grid" routine that I wrote as a quick hack for this purpose." There is an
attached file "tri-holes.ctl" for PCFs. I attache it in this letter again.
However, In this file, it includes a file "poly.scm",which I think is the
routine that metioned above. I have searched for this file, but have no any
results. Does anyone have this file and be so kind to send me a copy? Or can
anybody give me a sample code to compute gap maps and guided modes for pcfs?
Many thanks!
--
Best wishes,
Sincerely,
Z.H.Woo
; 2d system: triangular lattice of air holes in dielectric
; This structure has a complete band gap (i.e. a gap in both TE and TM
; simultaneously) for a hole radius of 0.45a and a dielectric constant of
; 12. (See, e.g., the book "Photonic Crystals" by Joannopoulos et al.)
; first, define the lattice vectors and k-points for a triangular lattice:
(set! geometry-lattice (make lattice (size 1 1 no-size)
(basis1 (/ (sqrt 3) 2) 0.5)
(basis2 (/ (sqrt 3) 2) -0.5)))
(define-param kz-min 0.2)
(define-param kz-max 2)
(define-param kxy-interp 7)
(define-param kz-interp 25)
(define Gamma (vector3 0 0 0))
(define M (vector3 0 0.5 0))
(define K (vector3 (/ -3) (/ 3) 0))
(define IBZ (list Gamma M K))
(include "poly.scm")
(define IBZ-grid (poly-grid IBZ kxy-interp kxy-interp 1 1))
(define-param boundaries-only? true)
(define-param gamma-only? false)
(if boundaries-only?
(set! k-points
(fold-left
append '()
(map
(lambda (kz)
(interpolate kxy-interp
(list (vector3 0 0 kz) ; Gamma
(vector3 0 0.5 kz) ; M
(vector3 (/ -3) (/ 3) kz) ; K
(vector3 0 0 kz) ; Gamma
)))
(interpolate kz-interp (list kz-min kz-max)))))
(set! k-points
(fold-left
append '()
(map
(lambda (kz)
(map (lambda (k) (vector3+ k (vector3 0 0 kz))) IBZ-grid))
(interpolate kz-interp (list kz-min kz-max))))))
(if gamma-only?
(set! k-points (interpolate kz-interp (list (vector3 0 0 kz-min)
(vector3 0 0 kz-max)))))
; Now, define the geometry, etcetera:
(define-param n 1.46) ; dielectric constant of silica
(define-param r 0.47) ; the hole radius
; hollow cylinder outer radius (can overlap) (defaults to no corner voids)
(define-param r-outer infinity)
(define C->L (compose cartesian->lattice vector3))
(define (hexagon r c m)
(list
(make block (center c) (material m) (size (* r (sqrt 4/3)) (* 2 r))
(e1 (C->L 1 0)) (e2 (C->L 0 1)))
(make block (center c) (material m) (size (* r (sqrt 4/3)) (* 2 r))
(e2 (C->L (/ (sqrt 3) 2) 0.5)) (e1 (C->L -0.5 (/ (sqrt 3) 2))))
(make block (center c) (material m) (size (* r (sqrt 4/3)) (* 2 r))
(e2 (C->L (/ (sqrt 3) 2) -0.5)) (e1 (C->L 0.5 (/ (sqrt 3) 2))))
))
(define-param hex? false)
(define diel (make dielectric (index n)))
(if hex?
(begin
(set! default-material diel)
(set! geometry (hexagon r (vector3 0) air)))
(set! geometry (list (make cylinder (center 0) (material diel)
(radius r-outer)
(height infinity))
(make cylinder (center 0) (material air)
(radius r) (height infinity)))))
(set-param! resolution 64)
(set-param! num-bands 50)
(run)
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