Dear Steven, MPB users, I'm a student and I write my final exam in potonic crystal fibers. It is a rather new topic for me and that is why I a a simple question. You can often see in papers or in presentations (e.g. L5-fiber by Steven G. Johnson) that there are areas where you have bandgaps. I took the mpb and simulate a simple photonic crystal in 2d (silica with air holes) with the proagation k-vector in z-direction. If you take the k-vector in x and y direction I understand the bandgaps but what's about a bandgap in z-direction?
In the following picture I like to know how to calculate the blue and red areas! http://nano.physik.hu-berlin.de/images/Stephan_bandgap.gif This is the modeplot of my program http://nano.physik.hu-berlin.de/images/Stephan_freqs.png Thank you very much in advanced! Best regards Stephan PS: And here is my program (set! geometry-lattice (make lattice (size 1 1 no-size) (basis1 (sqrt 0.75) 0.5) (basis2 (sqrt 0.75) -0.5))) (define-param kx 0) (define-param ky 0) (set! k-points (list (vector3 kx ky 0) (vector3 kx ky 3))) (set! k-points (interpolate 16 k-points)) (define-param eps 2.1316) ;refraction index silica (define-param r 0.45) (set! default-material (make dielectric (epsilon eps))) (set! geometry (list (make cylinder (center 0) (material air) (radius r) (height infinity)))) (set-param! resolution 32) (set-param! num-bands 8) (run) ;grep by freqs and plot _______________________________________________ mpb-discuss mailing list mpb-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss
