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from __future__ import division, print_function
import meep as mp
import math
resolution = 50
sxy = 4
dpml = 1
cell = mp.Vector3(sxy+2*dpml,sxy+2*dpml,0)
pml_layers = mp.PML(dpml)
fcen = 1.0
df = 0.4
src_cmpt = mp.Ez
sources = mp.Source(src=mp.GaussianSource(fcen,fwidth=df),
center=mp.Vector3(),
component=src_cmpt)
if src_cmpt == mp.Ex:
symmetries = [mp.Mirror(mp.Y)]
elif src_cmpt == mp.Ey:
symmetries = [mp.Mirror(mp.X)]
elif src_cmpt == mp.Ez:
symmetries = [mp.Mirror(mp.X), mp.Mirror(mp.Y)]
sim = mp.Simulation(cell_size=cell,
resolution=resolution,
sources=[sources],
symmetries=symmetries,
boundary_layers=[pml_layers])
nearfield_box = sim.add_near2far(fcen, 0, 1,
mp.Near2FarRegion(mp.Vector3(y=0.5*sxy), size=mp.Vector3(sxy)),
mp.Near2FarRegion(mp.Vector3(y=-0.5*sxy), size=mp.Vector3(sxy), weight=-1),
mp.Near2FarRegion(mp.Vector3(0.5*sxy), size=mp.Vector3(y=sxy)),
mp.Near2FarRegion(mp.Vector3(-0.5*sxy), size=mp.Vector3(y=sxy), weight=-1))
flux_box = sim.add_flux(fcen, 0, 1,
mp.FluxRegion(mp.Vector3(y=0.5*sxy), size=mp.Vector3(sxy)),
mp.FluxRegion(mp.Vector3(y=-0.5*sxy), size=mp.Vector3(sxy), weight=-1),
mp.FluxRegion(mp.Vector3(0.5*sxy), size=mp.Vector3(y=sxy)),
mp.FluxRegion(mp.Vector3(-0.5*sxy), size=mp.Vector3(y=sxy), weight=-1))
sim.run(until_after_sources=mp.stop_when_fields_decayed(50, src_cmpt, mp.Vector3(), 1e-8))
flux = mp.get_fluxes(flux_box)
print("flux:, {}".format(flux[0]))
r = 1000/fcen # 1000 wavelengths out from the source
npts = 100 # number of points in [0,2*pi) range of angles
for n in range(npts):
ff = sim.get_farfield(nearfield_box, mp.Vector3(r*math.cos(2*math.pi*n/npts),
r*math.sin(2*math.pi*n/npts)))
print("farfield:, {}, {}, ".format(n, 2*math.pi*n/npts), end='')
print(", ".join([str(f).strip('()').replace('j', 'i') for f in ff]))
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