triangular lattice of air holes PC slab with defect line's band structure

Dear Pro.Steven and others,

I want to plot the band structure of photonic crystals slab with defect line
which is used as waveguide.
One example is shown by Fig.7 in steven's paper"Linear waveguides in
photonic-crystal slabs".
The structure is triangular lattice of air holes extending through both a
high-index ~e of 12.0! finite-height dielectric slab and low-index ~e
of 2.0! semi-infinite dielectric regions above and below. The holes have
lattice constant a and radius 0.3a, while the high-index slab is
of thickness 0.5a.
 I simulate this structure in MPB and get the band structure.
 The band structrue looks similar to steven's Fig.7,at least the trend
is.But my figure is a little lower at each point compared with Fig.7.
I can't find what the problem is.Anyone can point out why my figure is lower
for the some structure?
I think I specified the correct geometry because I check by h5topng,and the
picture is shown below:


xy plane                 xz plane                          yz plane

         I think there must be something wrong with my run function.


Thank you for your reply!

my CTL file is:

===============================================================================================

;these codes are referencing the Fig.7 in Steven's paper "Linear waveguides
;in photonic crystal slabs", PRB, Vol.62, p8212
;written by Ryan Hao, March,7rd,2007

(define-param h 0.5) ; the thickness of the slab
(define-param eps 12) ; the dielectric constant of the slab
(define-param cladeps 2) ; the dielectric constant of the cladding and
substrate
(define-param r 0.30 ) ; the radius of the holes
(define-param R 0.48)  ; the radius of the waveguide holes
(define-param supercell-h 6) ; height of the supercell
(define-param supercell-y 7) ; the (odd) number of lateral supercell periods


(set! geometry-lattice (make lattice(size 1  supercell-y supercell-h)
    (basis1 (/ (sqrt 3) 2) 0.5)
    (basis2 (/ (sqrt 3) 2) -0.5)

    ))


(set! geometry
      (list (make block (material (make dielectric (epsilon cladeps)))
                  (center 0) (size infinity infinity supercell-h))
            (make block (material (make dielectric (epsilon eps)))
                  (center 0) (size infinity infinity h))))

(set! geometry
        (append geometry
                (geometric-objects-lattice-duplicates
                        (list
                             (make cylinder (material air)
                             (center 0 0 0) (radius r) (height
supercell-h)))
    1 1 supercell-h)))
(set! geometry
        (append geometry
             (list (make cylinder (material  air)
                     (center 0 0 0) (radius R) (height supercell-h)))
;define the defect of the clad layer(fill in)


 ))


; 1st Brillouin zone of a triangular lattice:
(define Gamma (vector3 0 0 0))
(define K' (lattice->reciprocal (vector3 0.5 0 0))) ; edge of Brillouin
zone.

(define-param only-K false) ; run with only-K=true to only do this k-point
(define-param k-interp 4)   ; the number of k points to interpolate
(if only-K
    (set! k-points (list K))
    (set! k-points (interpolate k-interp (list Gamma K'))))

(set-param! resolution (vector3 20 20 20))
(set-param! mesh-size 7)
(set-param! num-bands 9)

; Run even and odd bands, outputting fields only at the K point:
(run-zeven )
;(run-zodd )

============================================================
===================================

Best wishes



                      Yours,
                      Ryan Hao



Wuhan National Laboratory for Optoelectronics
Institute of Optoelectronic Sinence and Engineering, HUST University
Wuhan, 430074, P.R.CHINA
Phone: 86-027-87792242-809(O)
Mobile:
Fax:

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