Re: Quasiperiodic Lattice

I am attempting to reproduce the anisotropic equifrequency surfaces from 
PRE 67,056607 (2003) figure 3. (b)
using the below control file but all equifrequency contours i obtain are 
symmetric.
Does anyone know why i am unable to observe the effect of anisotropy 
using find-k in this case.
Thanks,
Aaron Matthews

;************* find-k parameters ************************************
(define-param freq 0.68)
(define-param band_min 2)
(define-param band_max 2)
(define-param tol 1e-8)
(define-param kmag_guess 0.1)
(define-param kmag_min 0.001)
(define-param kmag_max 0.75)
;************ geometry parameters ***********************************
(set! resolution 64)
(set! geometry-lattice (make lattice (size 1 1 no-size)
                         (basis1 0.5 0.5)
                         (basis2 0.5 -0.5)))
(set! default-material (make dielectric (epsilon 1.06)))
(set! geometry (list (make cylinder (center 0 0 0) (radius 0.4)
        (height infinity) (material (make dielectric-anisotropic 
(epsilon-diag (vector3  2.3165 2.91 2.3165)))))
))
;************ k direction values ************************************
(define init-kdir (vector3 1 0 0))
(define kdir (vector3 1 0 0))
(define angular-steps 361)
(define ang (deg->rad 360))
(define ang-step (/ ang angular-steps))
;************ no k error handler ************************************
(define no-k
    (lambda (key . args) (print "\n ---- no k ---- \n\n") ))
;************ wave vector finding routine ***************************
(define end 1)
(define n 0)
(while (= end 1)
    (catch #t
    (lambda()
    (find-k TM freq band_min band_max kdir tol kmag_guess kmag_min 
kmag_max)) no-k)
    (set! kdir (rotate-vector3 (vector3 0 0 1)(* n ang-step) init-kdir))
    (if (= n angular-steps) (set! end 0)(set! n (+ n 1))) )
;********************************************************************

-- 
Aaron Matthews
Research scholar
Nonlinear Physics Centre
Research School of Physical Sciences and Engineering
The Australian National University
Canberra ACT 0200
Tel:  +61-2-6125-8277
Fax:  +61-2-6125-8588
Email:[email protected]