Dear Meep users, The subject of 3D plane waves seems to have been discussed here before, but I have some trouble implementing it. In a previous discussion, three methods for generating 2D plane waves have been presented.
For the two methods mentioned here http://ab-initio.mit.edu/pipermail/meep-discuss/2007-December/001280.html , codes have been presented by Steven (where multiple sources are needed in the 3D case), and by Matt and Ashifi (using one source and periodic boundary conditions) I modified their codes to try to generate 3D plane waves. The code that appears below creates a wave that propagates in the Z direction, with periodic Ey, Hx and Hz components and (almost) zero Ex, Ez and Hy components. That means that is could have been a plane wave, if only the Hz component would be zero Perhaps someone has a hint how to do this correctly? best, avner ;;________________________________________________________________________________ (use-output-directory) ; put all output in a new directory (define-param source-component Ey) ; field component to use (define-param kdir (vector3 1 0 0)) ;direction of PW equal phase lines (define-param fcen 0.8) ; pulse center frequency (define-param df 0.02) ; turn-on bandwidth (define wlength (/ 1 fcen)) ; pulse wavelength (define-param sxy 8) ; the size of the comp cell in X and Y, not including PML (define-param dpml 3) ; thickness of PML layers ; set periodicity in the X direction. The PML takes care of the ; non-desired Y periodicity that comes for free with the k-point declaration (set! k-point (vector3 0 0 0)) (set! ensure-periodicity true) (define sz (+ sxy (* 2 dpml))) ; cell size in Z direction, including PML (set! geometry-lattice (make lattice (size sxy sxy sz))) ; we'll only have PML in the Y direction (top and bottom) (set! pml-layers (list (make pml (thickness dpml) (direction Z)))) (set-param! resolution 5) ; pw-amp is a function that returns the amplitude exp(ik(x+x0)) at a ; given point x. (We need the x0 because current amplitude functions ; in Meep are defined relative to the center of the current source, ; whereas we want a fixed origin.) Actually, it is a function of k ; and x0 that returns a function of x ... (define ((pw-amp k x0) x) (exp (* 0+1i (vector3-dot k (vector3+ x x0))))) ; k with correct length (define k (vector3-scale (* 2 pi fcen) (unit-vector3 kdir))) (set! sources (list (make source (src (make continuous-src (frequency fcen) (fwidth df))) (component source-component) (center (* -0.5 sxy) (* -0.5 sxy) (* -0.5sxy) ) (size sxy sxy) (amp-func (pw-amp k (vector3 (* -0.5 sxy) (* -0.5 sxy) (* -0.5sxy))))) )) (run-until 40 (at-end output-efield-z output-efield-y output-efield-x output-hfield-x output-hfield-y output-hfield-z)) ;;_______________________________________________________________________________________________________
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