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import meep as mp
eps = 13 # dielectric constant of waveguide
w = 1.2 # width of waveguide
r = 0.36 # radius of holes
d = 1.4 # defect spacing (ordinary spacing = 1)
N = 3 # number of holes on either side of defect
sy = 6 # size of cell in y direction (perpendicular to wvg.)
pad = 2 # padding between last hole and PML edge
dpml = 1 # PML thickness
sx = 2 * (pad + dpml + N) + d - 1 # size of cell in x direction
cell = mp.Vector3(sx, sy, 0)
geometry = [mp.Block(center=mp.Vector3(), size=mp.Vector3(mp.inf, w, mp.inf),
material=mp.Medium(epsilon=eps))]
for i in range(N):
geometry.append(mp.Cylinder(r, center=mp.Vector3(d / 2 + i)))
geometry.append(mp.Cylinder(r, center=mp.Vector3(d / -2 - i)))
pml_layers = mp.PML(dpml)
resolution = 20
fcen = 0.25 # pulse center frequency
df = 0.2 # pulse width (in frequency)
sources = mp.Source(src=mp.GaussianSource(fcen, fwidth=df), component=mp.Hz, center=mp.Vector3())
symmetries = [mp.Mirror(mp.Y, phase=-1), mp.Mirror(mp.X, phase=-1)]
d1 = 0.2
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
sources=[sources],
symmetries=symmetries,
boundary_layers=[pml_layers],
resolution=resolution)
nearfield = sim.add_near2far(
fcen, 0, 1,
mp.Near2FarRegion(mp.Vector3(0, 0.5 * w + d1), size=mp.Vector3(2 * dpml - sx)),
mp.Near2FarRegion(mp.Vector3(-0.5 * sx + dpml, 0.5 * w + 0.5 * d1), size=mp.Vector3(0, d1), weight=-1.0),
mp.Near2FarRegion(mp.Vector3(0.5 * sx - dpml, 0.5 * w + 0.5 * d1), size=mp.Vector3(0, d1))
)
sim.run(until_after_sources=mp.stop_when_fields_decayed(50, mp.Hz, mp.Vector3(0.12, -0.37), 1e-8))
d2 = 20
h = 4
sim.output_farfields(nearfield, "spectra-{}-{}-{}".format(d1, d2, h), resolution,
where=mp.Volume(mp.Vector3(0, (0.5 * w) + d2 + (0.5 * h)),
size=mp.Vector3(sx - 2 * dpml, h)))
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