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import argparse
import numpy as np
from meep.materials import Ag
import meep as mp
parser = argparse.ArgumentParser()
parser.add_argument("-res", type=int, default=50, help="resolution (pixels/um)")
parser.add_argument("-nf", type=int, default=500, help="number of frequencies")
parser.add_argument(
"-nsrc",
type=int,
default=15,
help="number of line sources with cosine Fourier series amplitude function (method 3)",
)
parser.add_argument(
"-textured",
action="store_true",
default=False,
help="flat (default) or textured surface",
)
parser.add_argument(
"-method",
type=int,
choices=[2, 3],
default=2,
help="type of method: (2) single dipole with 1 run per dipole or (3) line source with cosine Fourier series amplitude function",
)
args = parser.parse_args()
resolution = args.res
dpml = 1.0
dair = 0.9
hrod = 0.6
wrod = 0.8
dsub = 5.4
dAg = 0.4
sx = 1.5
sy = dpml + dair + hrod + dsub + dAg
cell_size = mp.Vector3(sx, sy)
pml_layers = [mp.PML(direction=mp.Y, thickness=dpml, side=mp.High)]
fcen = 1.0
df = 0.2
nfreq = args.nf
nsrc = args.nsrc
ndipole = int(sx * resolution)
run_time = 2 * nfreq / df
geometry = [
mp.Block(
material=mp.Medium(index=3.45),
center=mp.Vector3(0, 0.5 * sy - dpml - dair - hrod - 0.5 * dsub),
size=mp.Vector3(mp.inf, dsub, mp.inf),
),
mp.Block(
material=Ag,
center=mp.Vector3(0, -0.5 * sy + 0.5 * dAg),
size=mp.Vector3(mp.inf, dAg, mp.inf),
),
]
if args.textured:
geometry.append(
mp.Block(
material=mp.Medium(index=3.45),
center=mp.Vector3(0, 0.5 * sy - dpml - dair - 0.5 * hrod),
size=mp.Vector3(wrod, hrod, mp.inf),
)
)
def src_amp_func(n):
def _src_amp_func(p):
if n == 0:
return 1 / np.sqrt(sx)
else:
return np.sqrt(2 / sx) * np.cos(n * np.pi * (p.x + 0.5 * sx) / sx)
return _src_amp_func
def compute_flux(m, n):
if m == 2:
sources = [
mp.Source(
mp.GaussianSource(fcen, fwidth=df),
component=mp.Ez,
center=mp.Vector3(
sx * (-0.5 + n / ndipole), -0.5 * sy + dAg + 0.5 * dsub
),
)
]
else:
sources = [
mp.Source(
mp.GaussianSource(fcen, fwidth=df),
component=mp.Ez,
center=mp.Vector3(0, -0.5 * sy + dAg + 0.5 * dsub),
size=mp.Vector3(sx, 0),
amp_func=src_amp_func(n),
)
]
sim = mp.Simulation(
cell_size=cell_size,
resolution=resolution,
k_point=mp.Vector3(),
boundary_layers=pml_layers,
geometry=geometry,
sources=sources,
)
flux_mon = sim.add_flux(
fcen,
df,
nfreq,
mp.FluxRegion(center=mp.Vector3(0, 0.5 * sy - dpml), size=mp.Vector3(sx)),
)
sim.run(until=run_time)
flux = mp.get_fluxes(flux_mon)
freqs = mp.get_flux_freqs(flux_mon)
return freqs, flux
if args.method == 2:
fluxes = np.zeros((nfreq, ndipole))
for d in range(ndipole):
freqs, fluxes[:, d] = compute_flux(2, d)
else:
fluxes = np.zeros((nfreq, nsrc))
for d in range(nsrc):
freqs, fluxes[:, d] = compute_flux(3, d)
if mp.am_master():
with open(
f'method{args.method}_{"textured" if args.textured else "flat"}_res{resolution}_nfreq{nfreq}_{"ndipole" if args.method == 2 else "nsrc"}{ndipole if args.method == 2 else nsrc}.npz',
"wb",
) as f:
np.savez(f, freqs=freqs, fluxes=fluxes)
|
