One of the reasons for seeing a pulse multiple times could be reflections. In your case, your PML is 2 cells wide (thickness is 0.1 at resolution of 20). How about making your PML thickness 1.0 instead?
Your pulse could be bouncing back and forth between the two Y walls inside your dielectric. Another thing you could do is to use (at-every 50 (output-png Ez "-Zc dkbluered")) in your (run-until...) statement so that you can confirm this reflection hypothesis from the images. If you use linux and/or cygwin and you have ImageMagick installed then you can animate your images using: animate -delay 10 -pause 2 <your-meep-filename>-ez*.png -- Manoj shiv chawla wrote: > Hello Everyone > > I am trying to simulate propagation of gaussian pulse in a dielectric > slab. I have added PML boundary on the right edge (at the end of > computational domain)..I am interested in observing Electric Field at > any given point however I see the same pulse several times in the output > (the pulse should appear once at a point). This is my code.... > > ( > > ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; > > ; Define the structure and the computational cell > > ; Here we define the size of the computational cell. Since it is 2d, > ; it has no-size in the z direction. > > (set! geometry-lattice (make lattice (size 20 10 no-size))) > > ; the default-material is what fills space where we haven't placed objects > (set! default-material (make dielectric (epsilon 1))) > > ; a list of geometric objects to create structures in our computational > cell: > ; (in this case, we only have one object, a block to make the waveguide) > (set! geometry > (list (make block ; a dielectric block (a rectangle) > (center 0 0 0) ; centered at origin > (size infinity 2 infinity) > (material (make dielectric (epsilon 2)))))) > > > (set-param! resolution 20) > > > (set! pml-layers (list (make pml (thickness 0.1) (direction X) (side High) > (make pml (thickness 0.1) (direction Y) (side Low)) > (make pml (thickness 0.1) (direction Y) (side > High))))) > > (define-param fcen 0.1) > (define-param df 0.15) > (set! sources (list (make source > (src (make gaussian-src (frequency fcen) (fwidth df))) > (component Ez) (center -9 0)))) > > (define (Field) > (print "Field:, " (meep-time) ", " > (get-field-point Ez (vector3 5 0 0)) "\n")) > > (run-until 1000 Field) > > > > What should be done in order to observe pulse only once at any point??? > > Thanks > > Regards > Shiv > IIT -Delhi > > ------------------------------------------------------------------------ > Get the freedom to save as many mails as you wish. Click here to know > how. > <http://in.rd.yahoo.com/tagline_mail_5/*http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/> > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > meep-discuss mailing list > [email protected] > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss _______________________________________________ meep-discuss mailing list [email protected] http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
