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# Meep Tutorial: Hz-polarized transmission and reflection through a cavity
# formed by a periodic sequence of holes in a dielectric waveguide,
# with a defect formed by a larger spacing between one pair of holes.
# This structure is based on one analyzed in:
# S. Fan, J. N. Winn, A. Devenyi, J. C. Chen, R. D. Meade, and
# J. D. Joannopoulos, "Guided and defect modes in periodic dielectric
# waveguides," J. Opt. Soc. Am. B, 12 (7), 1267-1272 (1995).
import meep as mp
def main():
# Some parameters to describe the geometry:
eps = 13 # dielectric constant of waveguide
w = 1.2 # width of waveguide
r = 0.36 # radius of holes
# The cell dimensions
sy = 12 # size of cell in y direction (perpendicular to wvg.)
dpml = 1 # PML thickness (y direction only!)
cell = mp.Vector3(1, sy)
b = mp.Block(size=mp.Vector3(mp.inf, w, mp.inf), material=mp.Medium(epsilon=eps))
c = mp.Cylinder(radius=r)
fcen = 0.25 # pulse center frequency
df = 1.5 # pulse freq. width: large df = short impulse
s = mp.Source(
src=mp.GaussianSource(fcen, fwidth=df),
component=mp.Hz,
center=mp.Vector3(0.1234),
)
sym = mp.Mirror(direction=mp.Y, phase=-1)
sim = mp.Simulation(
cell_size=cell,
geometry=[b, c],
sources=[s],
symmetries=[sym],
boundary_layers=[mp.PML(dpml, direction=mp.Y)],
resolution=20,
)
kx = False # if true, do run at specified kx and get fields
if kx:
sim.k_point = mp.Vector3(kx)
sim.run(
mp.at_beginning(mp.output_epsilon),
mp.after_sources(mp.Harminv(mp.Hz, mp.Vector3(0.1234), fcen, df)),
until_after_sources=300,
)
sim.run(mp.at_every(1 / fcen / 20, mp.output_hfield_z), until=1 / fcen)
else:
k_interp = 19 # # k-points to interpolate, otherwise
sim.run_k_points(300, mp.interpolate(k_interp, [mp.Vector3(), mp.Vector3(0.5)]))
if __name__ == "__main__":
main()
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