Hello Meep users,
using the Python interface, I simulate a scatter-problem with PML in y-direction and a grating with periodic boundary conditions in x-direction. The periodic structure is made of silver.
The distance between source and scatterer is high enough to not influence the LDOS at the source location. Also the padding between scatterer and PML is high enough.
My target is to measure the reflectance by letting a p-polarized plane wave propagating in different angles (from 10 to 35 degree) on the scatterer and then plot the reflectance over the angles. Right now I am doing for every degree a simulation without scatterer (for normalisation) and with the scatterer.
Between 10 and 20 degree the measured reflectance looks good and almost matches the measured reflectance of a component build at the university laboratory (I am using the specifications of that component to verify the simulation set up).
After 20 degree to 35 degree the reflectance get messed up (see attachment if you like). At 25 degree the reflectance drop off, but it should be about 1, the same at 33 degree.
I use the plane wave amp function build by Steven G Johnson with specifying the kdir-vector for the incident angle (math is m and cmath is cm).
wavelength = 0.6328 fcen = 1/wavelength df = wavelength phi_pw = (2*m.pi/360)*rot_degree def pw_amp(k, x0): def _pw_amp(x): return cm.exp(1j * k.dot(x + x0)) return _pw_amp kdir = mp.Vector3(m.sin(phi_pw), m.cos(phi_pw)) k = kdir.unit().scale(2 * m.pi * fcen) sources = [mp.Source(mp.GaussianSource(fcen, fwidth = df), component = mp.Hz, center = mp.Vector3(0,0.4*y), size = mp.Vector3(x,0), amp_func=pw_amp(k, mp.Vector3(y = 0.4*y)))]Now it is not exactly like the pw-example by Steven G Johnson. I have only ONE source at the +y boundary. In my Simulation the computational cell got the size of x = 0.8 and y = 2.2 (without PML) and I don’t know how exactly I can implement the pw source with two interfer sources like this:
https://github.com/stevengj/meep/blob/master/python/examples/pw-source.pyCan please anyone help me to set up my source so in the cell to get the right incident angles.
Best Regards Christoph
Plot of Ref.pdf
Description: Adobe PDF document
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