On Thu, 17 Aug 2006, G.J. Parker wrote:
what i'm seeing is that R and T are NOT the same at each plane. in particular, at large frequencies, there is some spurious (?) oscillations in R & T which depend on the position of the flux planes. since there is nothing but air between the various flux planes, it appears energy is not conserved.
A couple possibilities come to mind, both related to the fact that you are using a very sharp input pulse to get a very broad bandwidth at once.
First, I seem to recall that the Fourier transforms run into some kind of numerical precision problems if you try to get too broad a bandwidth at once. (This is something I never looked at in detail, just something I remember from our old Fortran code years ago...since then I rarely use bandwidths more than 50%, just from habit.)
Second, if you have a sharp feature in the spectrum around there, you may not be running long enough for the spectrum to be converged thanks to the usual uncertainty principle. Remember, you have a short broad-band pulse, so only a tiny portion of your incident energy may be at the resonant frequency---this makes looking at the decay of the total energy, as you are doing, possibly deceptive.
Steven _______________________________________________ meep-discuss mailing list [email protected] http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
