Hello Matt, one thing you are experiencing has also happened one time to me. When you have transmission factors with levels above 1, it is because you usually need more time in the simulation. It means, you need to provide more time in order for all the waves to get through the plane detector. After doing that, the normalization works really good.
Other thing, for the source I usually work with Hz, but maybe for this purpose does not matter. Just in case. Another theme: have you worked with flux-in-box functions to calculate Q factor? I am having some problems with that. My calculations do not agree with those of MEEP. Thank you, Gerardo. 2010/6/18 <[email protected]> > Send meep-discuss mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of meep-discuss digest..." > > > Today's Topics: > > 1. Re: meep-discuss Digest, Vol 52, Issue 15 (G S) > 2. Re: Oblique Incience (Matthew Miskiewicz) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 18 Jun 2010 20:22:57 +0200 > From: G S <[email protected]> > Subject: Re: [Meep-discuss] meep-discuss Digest, Vol 52, Issue 15 > To: [email protected] > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="iso-8859-1" > > Hello Matt, > > the output seems to be truncated, is it that what you are also seeing when > you refer as "funny effect"? > > I want to help, but I don't understand very clearly the following lines of > your program: > > (define-param kdir (vector3 (cos theta_rad) (sin theta_rad))) > (define k (vector3-scale (* 2 pi fcen) kdir)) > > (define ((pw-amp k) y) (exp (* 0+1i (vector3-dot k y))) ) > > Why do you define k using (* 2 pi fcen) and do not use kdir directly? As > far > as I understand in meep one uses the vector directly, without scales. And, > what about the vector3-dot with the imaginary part. What literature are you > using? > > Hope it helps, > Gerardo. > > > > 2010/6/18 <[email protected]> > > > Send meep-discuss mailing list submissions to > > [email protected] > > > > To subscribe or unsubscribe via the World Wide Web, visit > > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > > or, via email, send a message with subject or body 'help' to > > [email protected] > > > > You can reach the person managing the list at > > [email protected] > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of meep-discuss digest..." > > > > > > Today's Topics: > > > > 1. Oblique Incience (Matthew Miskiewicz) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Thu, 17 Jun 2010 12:57:26 -0400 > > From: Matthew Miskiewicz <[email protected]> > > Subject: [Meep-discuss] Oblique Incience > > To: [email protected] > > Message-ID: > > <[email protected]> > > Content-Type: text/plain; charset="iso-8859-1" > > > > Hi, > > > > I'm learning to use meep and am attempting some simple simulations. I'm > > getting a weird result when calculating the wideband transmission of a > > plane > > wave at oblique incidence on a thin dielectric slab. When I use normal > > incidence, I get a perfect result. For oblique incidence, the > oscillations > > in the transmission look correct, but something else funny is happening. > > Any ideas on how to fix this? Is something set up wrong in the ctl > file? > > > > Picture of transmission: > > > > > http://picasaweb.google.com/lh/photo/wxSYCr_M9_PsHYS_Klllzr00Wanc329Uua6LuGynryc?feat=directlink > > > > Thanks! > > Matt Miskiewicz > > > > Research Assistant, Optoelectronics and Lightwave Engineering Group > > North Carolina State University > > > > > > > > Here is the ctl file: > > > > (define-param pmlthick 2) > > (define-param sy .5) > > (define-param sx 10) > > (define-param ref true) > > > > > > (set! geometry-lattice (make lattice (size (+ sx (* pmlthick 2)) sy > > no-size))) > > (set! geometry (list > > (make block (center 0 0) (size (- sx 5) sy) > > (material (make dielectric (index (if ref 1 > 1.5))))))) > > > > > > (set! resolution 30) > > > > (set! pml-layers (list (make pml (thickness pmlthick) (direction X)))) > > > > (define-param theta_deg 0) ; angle in degrees. > > (define theta_rad (/ (* pi theta_deg) 180)) > > (define-param fcen 0.75) ; pulse center frequency > > (define-param df 0.5) ; pulse bandwidth > > (define-param dfe 0.5) ; data extraction bandwidth > > (define wlength (/ 1 fcen)) ; pulse wavelength > > (define-param kdir (vector3 (cos theta_rad) (sin theta_rad))) > > (define k (vector3-scale (* 2 pi fcen) kdir)) > > > > (define ((pw-amp k) y) > > (exp (* 0+1i (vector3-dot k y)))) > > > > (set-param! k-point (vector3 0 (* fcen (sin theta_rad)) 0)) > > > > (set! sources (list > > (make source > > (src (make gaussian-src (frequency fcen) (fwidth df))) > > (component Ez) > > (center (+(/ sx -2) 1) 0) > > (size 0 sy 0) > > (amp-func (pw-amp k))))) > > > > (define-param nfreq 200) ; number of frequencies at which to compute flux > > (define trans ; transmitted flux > > (add-flux fcen dfe nfreq > > (make flux-region > > (center (- (/ sx 2) 1) 0) (size 0 sy)))) > > > > (run-until 10000) > > > > (display-fluxes trans) > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://ab-initio.mit.edu/pipermail/meep-discuss/attachments/20100617/bc919741/attachment.html > > > > > > > ------------------------------ > > > > _______________________________________________ > > meep-discuss mailing list > > [email protected] > > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > > > > End of meep-discuss Digest, Vol 52, Issue 15 > > ******************************************** > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://ab-initio.mit.edu/pipermail/meep-discuss/attachments/20100618/851c8e0f/attachment-0001.htm > > > > ------------------------------ > > Message: 2 > Date: Fri, 18 Jun 2010 15:19:56 -0400 > From: Matthew Miskiewicz <[email protected]> > Subject: Re: [Meep-discuss] Oblique Incience > To: [email protected] > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Gerardo, > > the output seems to be truncated, is it that what you are also seeing when > > you refer as "funny effect"? > > > Maybe, I am not sure what you mean by truncated. What I see wrong in the > output is that transmission seems to have a decaying exponential factor, > and > also goes greater than 1 at some points. I expect to see just a sinusoidal > shape with the consistent peak/trough magnitudes. > > > (define-param kdir (vector3 (cos theta_rad) (sin theta_rad))) > > (define k (vector3-scale (* 2 pi fcen) kdir)) > > > > (define ((pw-amp k) y) (exp (* 0+1i (vector3-dot k y))) ) > > > > Why do you define k using (* 2 pi fcen) and do not use kdir directly? As > > far as I understand in meep one uses the vector directly, without scales. > > And, what about the vector3-dot with the imaginary part. What literature > are > > you using? > > > > I'll try to explain these lines: > > kdir is the direction of the wavevector. > k is the wavevector itself, which is the direction scaled by the > wavenumber. In this case, I don't think we can use kdir directly. > pw-amp is function to be multiplied with the source. It only modulates the > phase of the source to produce the desired angle, which is why is has the > vector3-dot 0+1i. > > Hm, I think I am beginning to see the, or at least a problem. This code > was > originally written for single frequency sources; with a gaussian source, I > don't think the pw-amp function will work as desired. Is there a way to > make oblique incidence gaussian sources? One idea that comes to mind is to > make the pw-amp function vary in time as the source is produced, but I > don't > know if that is even possible. > > Also, as for the source, I got this code from a post I found on the > meep-discuss archives by searching "oblique". > > Thanks for the reply, I think you got me on the right track, > Matt > > On Fri, Jun 18, 2010 at 2:22 PM, G S <[email protected]> wrote: > > > Hello Matt, > > > > the output seems to be truncated, is it that what you are also seeing > when > > you refer as "funny effect"? > > > > I want to help, but I don't understand very clearly the following lines > of > > your program: > > > > (define-param kdir (vector3 (cos theta_rad) (sin theta_rad))) > > (define k (vector3-scale (* 2 pi fcen) kdir)) > > > > (define ((pw-amp k) y) (exp (* 0+1i (vector3-dot k y))) ) > > > > Why do you define k using (* 2 pi fcen) and do not use kdir directly? As > > far as I understand in meep one uses the vector directly, without scales. > > And, what about the vector3-dot with the imaginary part. What literature > are > > you using? > > > > Hope it helps, > > Gerardo. > > > > > > > > 2010/6/18 <[email protected]> > > > >> Send meep-discuss mailing list submissions to > >> [email protected] > >> > >> To subscribe or unsubscribe via the World Wide Web, visit > >> http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > >> or, via email, send a message with subject or body 'help' to > >> [email protected] > >> > >> You can reach the person managing the list at > >> [email protected] > >> > >> When replying, please edit your Subject line so it is more specific > >> than "Re: Contents of meep-discuss digest..." > >> > >> > >> Today's Topics: > >> > >> 1. Oblique Incience (Matthew Miskiewicz) > >> > >> > >> ---------------------------------------------------------------------- > >> > >> Message: 1 > >> Date: Thu, 17 Jun 2010 12:57:26 -0400 > >> From: Matthew Miskiewicz <[email protected]> > >> Subject: [Meep-discuss] Oblique Incience > >> To: [email protected] > >> Message-ID: > >> <[email protected]> > >> Content-Type: text/plain; charset="iso-8859-1" > >> > >> Hi, > >> > >> I'm learning to use meep and am attempting some simple simulations. I'm > >> getting a weird result when calculating the wideband transmission of a > >> plane > >> wave at oblique incidence on a thin dielectric slab. When I use normal > >> incidence, I get a perfect result. For oblique incidence, the > >> oscillations > >> in the transmission look correct, but something else funny is happening. > >> Any ideas on how to fix this? Is something set up wrong in the ctl > file? > >> > >> Picture of transmission: > >> > >> > http://picasaweb.google.com/lh/photo/wxSYCr_M9_PsHYS_Klllzr00Wanc329Uua6LuGynryc?feat=directlink > >> > >> Thanks! > >> Matt Miskiewicz > >> > >> Research Assistant, Optoelectronics and Lightwave Engineering Group > >> North Carolina State University > >> > >> > >> > >> Here is the ctl file: > >> > >> (define-param pmlthick 2) > >> (define-param sy .5) > >> (define-param sx 10) > >> (define-param ref true) > >> > >> > >> (set! geometry-lattice (make lattice (size (+ sx (* pmlthick 2)) sy > >> no-size))) > >> (set! geometry (list > >> (make block (center 0 0) (size (- sx 5) sy) > >> (material (make dielectric (index (if ref 1 > 1.5))))))) > >> > >> > >> (set! resolution 30) > >> > >> (set! pml-layers (list (make pml (thickness pmlthick) (direction X)))) > >> > >> (define-param theta_deg 0) ; angle in degrees. > >> (define theta_rad (/ (* pi theta_deg) 180)) > >> (define-param fcen 0.75) ; pulse center frequency > >> (define-param df 0.5) ; pulse bandwidth > >> (define-param dfe 0.5) ; data extraction bandwidth > >> (define wlength (/ 1 fcen)) ; pulse wavelength > >> (define-param kdir (vector3 (cos theta_rad) (sin theta_rad))) > >> (define k (vector3-scale (* 2 pi fcen) kdir)) > >> > >> (define ((pw-amp k) y) > >> (exp (* 0+1i (vector3-dot k y)))) > >> > >> (set-param! k-point (vector3 0 (* fcen (sin theta_rad)) 0)) > >> > >> (set! sources (list > >> (make source > >> (src (make gaussian-src (frequency fcen) (fwidth df))) > >> (component Ez) > >> (center (+(/ sx -2) 1) 0) > >> (size 0 sy 0) > >> (amp-func (pw-amp k))))) > >> > >> (define-param nfreq 200) ; number of frequencies at which to compute > flux > >> (define trans ; transmitted flux > >> (add-flux fcen dfe nfreq > >> (make flux-region > >> (center (- (/ sx 2) 1) 0) (size 0 sy)))) > >> > >> (run-until 10000) > >> > >> (display-fluxes trans) > >> -------------- next part -------------- > >> An HTML attachment was scrubbed... > >> URL: < > >> > http://ab-initio.mit.edu/pipermail/meep-discuss/attachments/20100617/bc919741/attachment.html > >> > > >> > >> ------------------------------ > >> > >> _______________________________________________ > >> meep-discuss mailing list > >> [email protected] > >> http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > >> > >> End of meep-discuss Digest, Vol 52, Issue 15 > >> ******************************************** > >> > > > > > > _______________________________________________ > > meep-discuss mailing list > > [email protected] > > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://ab-initio.mit.edu/pipermail/meep-discuss/attachments/20100618/1885a5d7/attachment.htm > > > > ------------------------------ > > _______________________________________________ > meep-discuss mailing list > [email protected] > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > > End of meep-discuss Digest, Vol 52, Issue 16 > ******************************************** >
_______________________________________________ meep-discuss mailing list [email protected] http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
