Hello,I've been trying to figure out why I'm getting errors for longer wavelengths when running the periodic scattering problem discussed earlier on the list.
What we tried was to calculate the transmission, reflection, and loss by accumulating reflected and transmitted fluxes. In this simple example, I'm just investigating a dielectric slab.
We use a gaussian source with bandwidth df = 0.5*fcen. There are periodic boundaries in the horizontal dimension, and PML in the vertical one.
In the attached plot, you can see that the coefficients get screwy for shorter frequencies. Before a certain wavelength, R and T are both between 0 and 1, and the loss is acceptably close to zero.
What I tried checking was if any dimensions were too small; PML thickness, cell width, and distances from flux planes to sources and scatterer. I also played with df, trying to make the source have a wider df than the flux regions. Finally, I increased the grid resolution, which also had no effect. I think gridding problems would manifest themselves at shorter wavelengths, so that makes sense.
Has anyone else experienced similar problems? http://www.pastebin.us/23054 touch asdf.h5 && rm *.h5 *.png comput* *~ && meep no-scatterer\?=true compute-flux\?=true test.ctl | tee lastrun.out && meep no-scatterer\?=false compute-flux\?=true test.ctl | tee -a lastrun.out Kind Regards, Matt
1.png
Description: scattering coeff. plot
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