fdtd.rar_FDTD photonic_FDTD 腔_meep_光子晶体

(define-param d (/ (sqrt 3) 2)) (define-param N 17) (define-param sy (* N d)) ; the (odd) number of lateral supercell periods (define-param dpml 1) (define-param pad 1) (define-param sx (+ (* (+ pad dpml) 2) N)) (define-param eps 12) ; the dielectric constant of the rods (define-param r 0.45) ; the rod radius in the bulk crystal (define-param rc 0.21) (define-param s 3) (set! geometry-lattice (make lattice (size sx sy no-size))) (set! geometry (append (list (make block (center 0 (* 0.5 d)) (size sx (* 2 d) infinity) (material (make dielectric (epsilon eps))))) (geometric-object-duplicates (vector3 1 0) 0 (/ (- N 1) 2) (make cylinder (center 0 0) (radius r) (height infinity) (material air))) (geometric-object-duplicates (vector3 -1 0) 0 (/ (- N 1) 2) (make cylinder (center 0 0) (radius r) (height infinity) (material air))) (geometric-object-duplicates (vector3 1 0) 0 (/ (- N 1) 2) (make cylinder (center 0.5 (* 1 d)) (radius r) (height infinity) (material air))) (geometric-object-duplicates (vector3 -1 0) 0 (/ (- N 1) 2) (make cylinder (center -0.5 (* 1 d)) (radius r) (height infinity) (material air))))) (set! geometry (geometric-objects-lattice-duplicates geometry infinity (* 2 d) infinity)) (set! geometry (append geometry (geometric-object-duplicates (vector3 1 0) 0 (/ (- N 1) 2) (make cylinder (center 0 0) (radius r) (height infinity) (material (make dielectric (epsilon eps))))) (geometric-object-duplicates (vector3 -1 0) 0 (/ (- N 1) 2) (make cylinder (center 0 0) (radius r) (height infinity) (material (make dielectric (epsilon eps))))) (geometric-object-duplicates (vector3 1 0) 0 (- s 1) (make cylinder (center 1 0) (radius rc) (height infinity) (material air))) (geometric-object-duplicates (vector3 -1 0) 0 (- s 1) (make cylinder (center -1 0) (radius rc) (height infinity) (material air))) )) (set! pml-layers (list (make pml (thickness dpml)))) (set-param! resolution 20) (define-param fcen 0.3629) ; pulse center frequency (define-param df 0.2) ; pulse width (in frequency) (define-param nfreq 500) ; number of frequencies at which to compute flux ; false = transmission spectrum, true = resonant modes: (define-param compute-mode? false) (if compute-mode? (begin (set! sources (list (make source (src (make gaussian-src (frequency fcen) (fwidth df))) (component Hz) (center 0 0)))) (run-sources+ 400 (at-beginning output-epsilon) (after-sources (harminv Hz (vector3 0) fcen df))) (run-until (/ 1 fcen) (at-every (/ 1 fcen 20) output-hfield-z)) ) (begin (set! sources (list (make source (src (make gaussian-src (frequency fcen) (fwidth df))) (component Ey) (center (+ (* -0.5 sx) dpml pad) 0) (size 0 (* 1 d))))) (define trans ; transmitted flux (add-flux fcen df nfreq (make flux-region (center (- (* 0.5 sx) dpml pad) 0) (size 0 (* 2 d))))) (run-sources+ 500 (at-beginning output-epsilon)) (display-fluxes trans) ; print out the flux spectrum ))