def run_mode_coeffs(self, mode_num, kpoint_func):
resolution = 15
w = 1 # width of waveguide
L = 10 # length of waveguide
Si = mp.Medium(epsilon=12.0)
dair = 3.0
dpml = 3.0
sx = dpml + L + dpml
sy = dpml + dair + w + dair + dpml
cell_size = mp.Vector3(sx, sy, 0)
prism_x = sx + 1
prism_y = w / 2
vertices = [
mp.Vector3(-prism_x, prism_y),
mp.Vector3(prism_x, prism_y),
mp.Vector3(prism_x, -prism_y),
mp.Vector3(-prism_x, -prism_y)
]
geometry = [mp.Prism(vertices, height=mp.inf, material=Si)]
boundary_layers = [mp.PML(dpml)]
# mode frequency
fcen = 0.20 # > 0.5/sqrt(11) to have at least 2 modes
sources = [
mp.EigenModeSource(src=mp.GaussianSource(fcen, fwidth=0.5 * fcen),
eig_band=mode_num,
size=mp.Vector3(0, sy - 2 * dpml, 0),
center=mp.Vector3(-0.5 * sx + dpml, 0, 0),
eig_match_freq=True,
eig_resolution=32)
]
sim = mp.Simulation(
resolution=resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
geometry=geometry,
sources=sources,
symmetries=[mp.Mirror(mp.Y, phase=1 if mode_num % 2 == 1 else -1)])
xm = 0.5 * sx - dpml # x-coordinate of monitor
mflux = sim.add_mode_monitor(
fcen, 0, 1,
mp.ModeRegion(center=mp.Vector3(xm, 0),
size=mp.Vector3(0, sy - 2 * dpml)))
mode_flux = sim.add_flux(
fcen, 0, 1,
mp.FluxRegion(center=mp.Vector3(xm, 0),
size=mp.Vector3(0, sy - 2 * dpml)))
# sim.run(until_after_sources=mp.stop_when_fields_decayed(50, mp.Ez, mp.Vector3(-0.5*sx+dpml,0), 1e-10))
sim.run(until_after_sources=100)
modes_to_check = [
1, 2
] # indices of modes for which to compute expansion coefficients
res = sim.get_eigenmode_coefficients(mflux,
modes_to_check,
kpoint_func=kpoint_func)
self.assertTrue(res.kpoints[0].close(mp.Vector3(0.604301, 0, 0)))
self.assertTrue(res.kpoints[1].close(mp.Vector3(0.494353, 0, 0),
tol=1e-2))
self.assertTrue(res.kdom[0].close(mp.Vector3(0.604301, 0, 0)))
self.assertTrue(res.kdom[1].close(mp.Vector3(0.494353, 0, 0),
tol=1e-2))
mode_power = mp.get_fluxes(mode_flux)[0]
TestPassed = True
TOLERANCE = 5.0e-3
c0 = res.alpha[
mode_num - 1, 0,
0] # coefficient of forward-traveling wave for mode #mode_num
for nm in range(1, len(modes_to_check) + 1):
if nm != mode_num:
cfrel = np.abs(res.alpha[nm - 1, 0, 0]) / np.abs(c0)
cbrel = np.abs(res.alpha[nm - 1, 0, 1]) / np.abs(c0)
if cfrel > TOLERANCE or cbrel > TOLERANCE:
TestPassed = False
self.sim = sim
# test 1: coefficient of excited mode >> coeffs of all other modes
self.assertTrue(TestPassed,
msg="cfrel: {}, cbrel: {}".format(cfrel, cbrel))
# test 2: |mode coeff|^2 = power
self.assertAlmostEqual(mode_power / abs(c0**2), 1.0, places=1)
return res
def main(args):
# Some parameters to describe the geometry:
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 = args.N # number of holes on either side of defect
# The cell dimensions
sy = args.sy # 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)
blk = mp.Block(size=mp.Vector3(1e20, w, 1e20),
material=mp.Medium(epsilon=eps))
geometry = [blk]
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))))
fcen = args.fcen # pulse center frequency
df = args.df # pulse frequency width
nfreq = 500 # number of frequencies at which to compute flux
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
sources=[],
boundary_layers=[mp.PML(dpml)],
resolution=20)
if args.resonant_modes:
sim.sources.append(
mp.Source(mp.GaussianSource(fcen, fwidth=df), mp.Hz, mp.Vector3()))
sim.symmetries.append(mp.Mirror(mp.Y, phase=-1))
sim.symmetries.append(mp.Mirror(mp.X, phase=-1))
sim.run( # mp.at_beginning(mp.output_epsilon),
mp.after_sources(mp.Harminv(mp.Hz, mp.Vector3(), fcen, df)),
until_after_sources=400)
# sim.run(mp.at_every(1 / fcen / 20, mp.output_hfield_z), until=1 / fcen)
else:
sim.sources.append(
mp.Source(mp.GaussianSource(fcen, fwidth=df),
mp.Ey,
mp.Vector3(dpml + (-0.5 * sx)),
size=mp.Vector3(0, w)))
sim.symmetries.append(mp.Mirror(mp.Y, phase=-1))
freg = mp.FluxRegion(center=mp.Vector3((0.5 * sx) - dpml - 0.5),
size=mp.Vector3(0, 2 * w))
# transmitted flux
trans = sim.add_flux(fcen, df, nfreq, freg)
vol = mp.Volume(mp.Vector3(), size=mp.Vector3(sx))
sim.run(mp.at_beginning(mp.output_epsilon),
mp.during_sources(
mp.in_volume(
vol,
mp.to_appended("hz-slice",
mp.at_every(0.4, mp.output_hfield_z)))),
until_after_sources=mp.stop_when_fields_decayed(
50, mp.Ey, mp.Vector3((0.5 * sx) - dpml - 0.5, 0), 1e-3))
sim.display_fluxes(trans) # print out the flux spectrum
def main(args=None):
fcen = 1 / 1.54
df = 0.1
wvg_width = .7
wvg_height = .22
dpml = 1
dpad = 2
sim2d = False
time_after_source = 500
eps_only = False
subz = True
resolution = 30
_nSi = 3.45
mode = get_excitation_mode("Ey")
# we want to investigate tuning. Change this to add a different material instead of air:
cover_material = mp.Medium(index=1.11)
if args is not None:
hx = args.diameter
hy = args.diameter
h_rel = args.h_rel
n = args.n
_nSi = args.n_si
nSi = mp.Medium(index=_nSi)
wvg = waveguide_1d(
wvg_width=wvg_width,
wvg_height=wvg_height,
material=nSi,
)
cav, cav_length = quadratic_radius_1d_symmetric(
n_segments=n,
hx=hx,
hy=hy,
h_rel=h_rel,
material_tuning=cover_material)
sx = dpml + dpad + cav_length + dpad + dpml
sy = dpml + dpad + wvg_width + dpad + dpml
sz = dpml + dpad + wvg_height + dpad + dpml
subs_height = (sz - wvg_height) / 2
subs = substrate(substrate_height=subs_height,
center=mp.Vector3(0, 0, -sz / 2 + subs_height / 2))
geometry = wvg + cav
symmetries = [
mp.Mirror(mp.X, +1),
mp.Mirror(mp.Y, -1),
mp.Mirror(mp.Z, +1)
]
if subz:
geometry = wvg + cav + subs
symmetries = [mp.Mirror(mp.X, +1), mp.Mirror(mp.Y, -1)]
boundary = get_boundary_layer(dpml, sim2d=sim2d)
if sim2d:
sz = 0
cell_size = mp.Vector3(sx, sy, sz)
sources = [
mp.Source(mp.GaussianSource(fcen, fwidth=df),
component=mode,
center=mp.Vector3())
]
sim = mp.Simulation(cell_size=cell_size,
geometry=geometry,
sources=sources,
boundary_layers=boundary,
symmetries=symmetries,
resolution=resolution,
progress_interval=100,
default_material=cover_material)
f = plt.figure(figsize=(10, 10))
sim.plot2D(ax=f.gca(),
output_plane=mp.Volume(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, 0)))
f.savefig("xy_plane.pdf", format="PDF")
f = plt.figure(figsize=(10, 10))
sim.plot2D(ax=f.gca(),
output_plane=mp.Volume(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, 0, sz)))
f.savefig("xz_plane.pdf", format="PDF")
f = plt.figure(figsize=(10, 10))
sim.plot2D(ax=f.gca(),
output_plane=mp.Volume(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(0, sy, sz)))
f.savefig("yz_plane.pdf", format="PDF")
h = mp.Harminv(mode, mp.Vector3(0, 0, 0), fcen, df)
# h_displaced = mp.Harminv(mode, mp.Vector3(0.05, 0.1, 0.02), fcen, df)
if eps_only:
sim.run(mp.at_beginning(mp.output_epsilon), until=0)
else:
# Don't output eps anymore to save disk space
sim.run(
mp.after_sources(h),
# mp.after_sources(h_displaced),
until_after_sources=time_after_source)
lcen = 0.5 # center wavelength
fcen = 1/lcen # center frequency
df = 0.2*fcen # frequency width
focal_length = 200 # focal length of metalens
spot_length = 100 # far field line length
ff_res = 10 # far field resolution (points/μm)
k_point = mp.Vector3(0,0,0)
glass = mp.Medium(index=1.5)
pml_layers = [mp.PML(thickness=dpml,direction=mp.X)]
symmetries=[mp.Mirror(mp.Y)]
def grating(gp,gh,gdc_list):
sx = dpml+dsub+gh+dpad+dpml
src_pt = mp.Vector3(-0.5*sx+dpml+0.5*dsub)
mon_pt = mp.Vector3(0.5*sx-dpml-0.5*dpad)
geometry = [mp.Block(material=glass,
size=mp.Vector3(dpml+dsub,mp.inf,mp.inf),
center=mp.Vector3(-0.5*sx+0.5*(dpml+dsub)))]
num_cells = len(gdc_list)
if num_cells == 1:
sy = gp
cell_size = mp.Vector3(sx,sy,0)
sources = [mp.Source(mp.GaussianSource(fcen, fwidth=df),
]
else:
sources = [
mp.Source(src=mp.GaussianSource(fsrc, fwidth=0.2 * fsrc)
if compute_flux else mp.ContinuousSource(fsrc),
center=mp.Vector3(),
size=mp.Vector3(y=3 * w),
component=mp.Ez)
]
sim = mp.Simulation(cell_size=cell_size,
resolution=resolution,
boundary_layers=pml_layers,
sources=sources,
geometry=geometry,
symmetries=[mp.Mirror(mp.Y)] if rot_angle == 0 else [])
if compute_flux:
tran = sim.add_flux(
fsrc, 0, 1, mp.FluxRegion(center=mp.Vector3(x=5),
size=mp.Vector3(y=14)))
sim.run(until_after_sources=50)
res = sim.get_eigenmode_coefficients(
tran, [1],
eig_parity=mp.EVEN_Y + mp.ODD_Z if rot_angle == 0 else mp.ODD_Z,
direction=mp.NO_DIRECTION,
kpoint_func=lambda f, n: kpoint)
print("flux:, {:.6f}, {:.6f}".format(
mp.get_fluxes(tran)[0],
abs(res.alpha[0, 0, 0])**2))
else:
def test_3d_with_symmetry(self):
self._test_3d([mp.Mirror(mp.X), mp.Mirror(mp.Y), mp.Mirror(mp.Z)])
def pec_ground_plane_radiation(self):
L = 8.0 # length of non-PML region
dpml = 1.0 # thickness of PML
sxy = dpml + L + dpml
cell_size = mp.Vector3(sxy, sxy, 0)
boundary_layers = [mp.PML(dpml)]
fcen = 1 / self.wvl
# The near-to-far field transformation feature only supports
# homogeneous media which means it cannot explicitly take into
# account the ground plane. As a workaround, we use two antennas
# of _opposite_ sign surrounded by a single near2far box which
# encloses both antennas. We then use an odd mirror symmetry to
# cut the computational cell in half which is effectively
# equivalent to a PEC boundary condition on one side.
# Note: This setup means that the radiation pattern can only
# be measured in the top half above the dipole.
sources = [
mp.Source(src=mp.GaussianSource(fcen, fwidth=0.2 * fcen),
component=self.src_cmpt,
center=mp.Vector3(0, +self.h)),
mp.Source(src=mp.GaussianSource(fcen, fwidth=0.2 * fcen),
component=self.src_cmpt,
center=mp.Vector3(0, -self.h),
amplitude=-1 if self.src_cmpt == mp.Ez else +1)
]
symmetries = [
mp.Mirror(direction=mp.X,
phase=+1 if self.src_cmpt == mp.Ez else -1),
mp.Mirror(direction=mp.Y,
phase=-1 if self.src_cmpt == mp.Ez else +1)
]
sim = mp.Simulation(resolution=self.resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
sources=sources,
symmetries=symmetries,
default_material=mp.Medium(index=self.n))
nearfield_box = sim.add_near2far(
fcen, 0, 1,
mp.Near2FarRegion(center=mp.Vector3(0, 2 * self.h),
size=mp.Vector3(2 * self.h, 0)),
mp.Near2FarRegion(center=mp.Vector3(0, -2 * self.h),
size=mp.Vector3(2 * self.h, 0),
weight=-1),
mp.Near2FarRegion(center=mp.Vector3(self.h, 0),
size=mp.Vector3(0, 4 * self.h)),
mp.Near2FarRegion(center=mp.Vector3(-self.h, 0),
size=mp.Vector3(0, 4 * self.h),
weight=-1))
sim.run(until_after_sources=mp.stop_when_dft_decayed())
Pr = self.radial_flux(sim, nearfield_box, self.r)
return Pr
dpml = 1
cell = mp.Vector3(sxy + 2 * dpml, sxy + 2 * dpml)
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.X, phase=-1), mp.Mirror(mp.Y, phase=+1)]
elif src_cmpt == mp.Ey:
symmetries = [mp.Mirror(mp.X, phase=+1), mp.Mirror(mp.Y, phase=-1)]
elif src_cmpt == mp.Ez:
symmetries = [mp.Mirror(mp.X, phase=+1), mp.Mirror(mp.Y, phase=+1)]
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(center=mp.Vector3(0, +0.5 * sxy),
size=mp.Vector3(sxy, 0)),
def test_get_point(self):
sxy = 6 # cell size
dpml = 1 # thickness of PML
def sinusoid(p):
r = (p.x**2+p.y**2)**0.5
return mp.Medium(index=1.0+math.sin(2*math.pi*r)**2)
geometry = [mp.Block(center=mp.Vector3(),
size=mp.Vector3(sxy,sxy),
material=sinusoid)]
src = [mp.Source(mp.GaussianSource(1.0, fwidth=0.1),
component=mp.Ez,
center=mp.Vector3())]
sim = mp.Simulation(cell_size=mp.Vector3(sxy,sxy),
geometry=geometry,
sources=src,
k_point=mp.Vector3(),
resolution=20,
symmetries=[mp.Mirror(mp.X),mp.Mirror(mp.Y)],
boundary_layers=[mp.PML(dpml)])
sim.run(until_after_sources=100)
## reference values for Ez and epsilon from serial run
ez_ref = [ -0.0002065983,
-0.0001954795,
-0.0000453570,
0.0000311267,
-0.0000121473,
-0.0000410032,
-0.0000341301,
-0.0000275021,
-0.0000397990,
-0.0000351730,
0.0000079602,
0.0000227437,
-0.0001092821,
-0.0002202751,
-0.0001408186,
0.0006325076,
0.0024890489,
0.0027476069,
0.0014815873,
0.0004714913,
-0.0004332029,
-0.0007101315,
-0.0003818581,
-0.0000748507,
0.0001408819,
0.0001119776,
0.0000395008,
0.0000078844,
-0.0000010431 ]
eps_ref = [ 1.6458346134,
1.2752837068,
1.0974010956,
1.0398089537,
1.0465784716,
1.0779924737,
1.1059439286,
1.1135579291,
1.0971979186,
1.0653178566,
1.0391657283,
1.0513779677,
1.1466009312,
1.3882154483,
1.8496939317,
2.5617731415,
3.3788212533,
3.9019494270,
3.6743431894,
2.7285622651,
1.6635165033,
1.0891237010,
1.1485969863,
1.9498398061,
3.3100416367,
3.9038800599,
2.8471862395,
1.4742605488,
1.0370162714 ]
x = np.linspace(-0.865692,2.692867,29)
places = 5 if mp.is_single_precision() else 10
for j in range(x.size):
self.assertAlmostEqual(np.real(sim.get_field_point(mp.Ez, mp.Vector3(x[j],-0.394862))),
ez_ref[j],
places=places)
self.assertAlmostEqual(sim.get_epsilon_point(mp.Vector3(x[j],2.967158)),
eps_ref[j],
places=places)
frq_min = 1/wvl_max
frq_max = 1/wvl_min
frq_cen = 0.5*(frq_min+frq_max)
dfrq = frq_max-frq_min
nfrq = 100
## at least 8 pixels per smallest wavelength, i.e. np.floor(8/wvl_min)
resolution = 25
dpml = 0.5*wvl_max
dair = 0.5*wvl_max
pml_layers = [mp.PML(thickness=dpml)]
symmetries = [mp.Mirror(mp.Y),
mp.Mirror(mp.Z,phase=-1)]
s = 2*(dpml+dair+r)
cell_size = mp.Vector3(s,s,s)
# is_integrated=True necessary for any planewave source extending into PML
sources = [mp.Source(mp.GaussianSource(frq_cen,fwidth=dfrq,is_integrated=True),
center=mp.Vector3(-0.5*s+dpml),
size=mp.Vector3(0,s,s),
component=mp.Ez)]
sim = mp.Simulation(resolution=resolution,
cell_size=cell_size,
boundary_layers=pml_layers,
sources=sources,
# moving point charge with superluminal phase velocity in dielectric media emitting Cherenkov radiation
import meep as mp
sx = 60
sy = 60
cell_size = mp.Vector3(sx, sy, 0)
dpml = 1.0
pml_layers = [mp.PML(thickness=dpml)]
v = 0.7 # velocity of point charge
symmetries = [mp.Mirror(direction=mp.Y)]
sim = mp.Simulation(resolution=10,
cell_size=cell_size,
default_material=mp.Medium(index=1.5),
symmetries=symmetries,
boundary_layers=pml_layers)
def move_source(sim):
sim.change_sources([
mp.Source(mp.ContinuousSource(frequency=1e-10),
component=mp.Ex,
center=mp.Vector3(-0.5 * sx + dpml + v * sim.meep_time()))
])
sim.run(move_source,
def run_mode_coeffs(self, mode_num, kpoint_func, nf=1, resolution=15):
w = 1 # width of waveguide
L = 10 # length of waveguide
Si = mp.Medium(epsilon=12.0)
dair = 3.0
dpml = 3.0
sx = dpml + L + dpml
sy = dpml + dair + w + dair + dpml
cell_size = mp.Vector3(sx, sy, 0)
prism_x = sx + 1
prism_y = w / 2
vertices = [
mp.Vector3(-prism_x, prism_y),
mp.Vector3(prism_x, prism_y),
mp.Vector3(prism_x, -prism_y),
mp.Vector3(-prism_x, -prism_y)
]
geometry = [mp.Prism(vertices, height=mp.inf, material=Si)]
boundary_layers = [mp.PML(dpml)]
# mode frequency
fcen = 0.20 # > 0.5/sqrt(11) to have at least 2 modes
df = 0.5 * fcen
source = mp.EigenModeSource(src=mp.GaussianSource(fcen, fwidth=df),
eig_band=mode_num,
size=mp.Vector3(0, sy - 2 * dpml, 0),
center=mp.Vector3(-0.5 * sx + dpml, 0, 0),
eig_match_freq=True,
eig_resolution=2 * resolution)
sim = mp.Simulation(
resolution=resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
geometry=geometry,
sources=[source],
symmetries=[mp.Mirror(mp.Y, phase=1 if mode_num % 2 == 1 else -1)])
xm = 0.5 * sx - dpml # x-coordinate of monitor
mflux = sim.add_mode_monitor(
fcen, df, nf,
mp.ModeRegion(center=mp.Vector3(xm, 0),
size=mp.Vector3(0, sy - 2 * dpml)))
mode_flux = sim.add_flux(
fcen, df, nf,
mp.FluxRegion(center=mp.Vector3(xm, 0),
size=mp.Vector3(0, sy - 2 * dpml)))
# sim.run(until_after_sources=mp.stop_when_fields_decayed(50, mp.Ez, mp.Vector3(-0.5*sx+dpml,0), 1e-10))
sim.run(until_after_sources=200)
##################################################
# If the number of analysis frequencies is >1, we
# are testing the unit-power normalization
# of the eigenmode source: we observe the total
# power flux through the mode_flux monitor (which
# equals the total power emitted by the source as
# there is no scattering in this ideal waveguide)
# and check that it agrees with the prediction
# of the eig_power() class method in EigenmodeSource.
##################################################
if nf > 1:
power_observed = mp.get_fluxes(mode_flux)
freqs = mp.get_flux_freqs(mode_flux)
power_expected = [source.eig_power(f) for f in freqs]
return freqs, power_expected, power_observed
modes_to_check = [
1, 2
] # indices of modes for which to compute expansion coefficients
res = sim.get_eigenmode_coefficients(mflux,
modes_to_check,
kpoint_func=kpoint_func)
self.assertTrue(res.kpoints[0].close(mp.Vector3(0.604301, 0, 0)))
self.assertTrue(res.kpoints[1].close(mp.Vector3(0.494353, 0, 0),
tol=1e-2))
self.assertTrue(res.kdom[0].close(mp.Vector3(0.604301, 0, 0)))
self.assertTrue(res.kdom[1].close(mp.Vector3(0.494353, 0, 0),
tol=1e-2))
self.assertAlmostEqual(res.cscale[0], 0.50000977, places=5)
self.assertAlmostEqual(res.cscale[1], 0.50096888, places=5)
mode_power = mp.get_fluxes(mode_flux)[0]
TestPassed = True
TOLERANCE = 5.0e-3
c0 = res.alpha[
mode_num - 1, 0,
0] # coefficient of forward-traveling wave for mode #mode_num
for nm in range(1, len(modes_to_check) + 1):
if nm != mode_num:
cfrel = np.abs(res.alpha[nm - 1, 0, 0]) / np.abs(c0)
cbrel = np.abs(res.alpha[nm - 1, 0, 1]) / np.abs(c0)
if cfrel > TOLERANCE or cbrel > TOLERANCE:
TestPassed = False
self.sim = sim
# test 1: coefficient of excited mode >> coeffs of all other modes
self.assertTrue(TestPassed,
msg="cfrel: {}, cbrel: {}".format(cfrel, cbrel))
# test 2: |mode coeff|^2 = power
self.assertAlmostEqual(mode_power / abs(c0**2), 1.0, places=1)
return res
def wvg_flux(self, res, att_coeff):
"""
Computes the Poynting flux in a single-mode waveguide at two
locations (5 and 10 μm) downstream from the source given the
grid resolution res (pixels/μm) and material attenuation
coefficient att_coeff (dB/cm).
"""
cell_size = mp.Vector3(14., 14.)
pml_layers = [mp.PML(thickness=2.)]
w = 1. # width of waveguide
fsrc = 0.15 # frequency (in vacuum)
# note: MPB can only compute modes of lossless material systems.
# The imaginary part of ε is ignored and the launched
# waveguide mode is therefore inaccurate. For small values
# of imag(ε) (which is proportional to att_coeff), this
# inaccuracy tends to be insignificant.
sources = [
mp.EigenModeSource(src=mp.GaussianSource(fsrc, fwidth=0.2 * fsrc),
center=mp.Vector3(-5.),
size=mp.Vector3(y=10.),
eig_parity=mp.EVEN_Y + mp.ODD_Z)
]
# ref: https://en.wikipedia.org/wiki/Mathematical_descriptions_of_opacity
# Note that this is the loss of a planewave, which is only approximately
# the loss of a waveguide mode. In principle, we could compute the latter
# semi-analytically if we wanted to run this unit test to greater accuracy
# (e.g. to test convergence with resolution).
n_eff = np.sqrt(12.) + 1j * (1 / fsrc) * (dB_cm_to_dB_um *
att_coeff) / (4 * np.pi)
eps_eff = n_eff * n_eff
# ref: https://meep.readthedocs.io/en/latest/Materials/#conductivity-and-complex
sigma_D = 2 * np.pi * fsrc * np.imag(eps_eff) / np.real(eps_eff)
geometry = [
mp.Block(center=mp.Vector3(),
size=mp.Vector3(mp.inf, w, mp.inf),
material=mp.Medium(epsilon=np.real(eps_eff),
D_conductivity=sigma_D))
]
sim = mp.Simulation(cell_size=cell_size,
resolution=res,
boundary_layers=pml_layers,
sources=sources,
geometry=geometry,
symmetries=[mp.Mirror(mp.Y)])
tran1 = sim.add_flux(
fsrc, 0, 1,
mp.FluxRegion(center=mp.Vector3(x=0.), size=mp.Vector3(y=10.)))
tran2 = sim.add_flux(
fsrc, 0, 1,
mp.FluxRegion(center=mp.Vector3(x=5.), size=mp.Vector3(y=10.)))
sim.run(until_after_sources=20)
return mp.get_fluxes(tran1)[0], mp.get_fluxes(tran2)[0]
def test_mode_decomposition(self):
resolution = 10
w1 = 1
w2 = 2
Lw = 2
dair = 3.0
dpml = 5.0
sy = dpml + dair + w2 + dair + dpml
half_w1 = 0.5 * w1
half_w2 = 0.5 * w2
Si = mp.Medium(epsilon=12.0)
boundary_layers = [mp.PML(dpml)]
lcen = 6.67
fcen = 1 / lcen
symmetries = [mp.Mirror(mp.Y)]
Lt = 2
sx = dpml + Lw + Lt + Lw + dpml
cell_size = mp.Vector3(sx, sy, 0)
prism_x = sx + 1
half_Lt = 0.5 * Lt
src_pt = mp.Vector3(-0.5 * sx + dpml + 0.2 * Lw, 0, 0)
sources = [
mp.EigenModeSource(src=mp.GaussianSource(fcen, fwidth=0.2 * fcen),
component=mp.Ez,
center=src_pt,
size=mp.Vector3(0, sy - 2 * dpml, 0),
eig_match_freq=True,
eig_parity=mp.ODD_Z + mp.EVEN_Y)
]
vertices = [
mp.Vector3(-prism_x, half_w1),
mp.Vector3(prism_x, half_w1),
mp.Vector3(prism_x, -half_w1),
mp.Vector3(-prism_x, -half_w1)
]
sim = mp.Simulation(
resolution=resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
geometry=[mp.Prism(vertices, height=mp.inf, material=Si)],
sources=sources,
symmetries=symmetries)
mon_pt = mp.Vector3(-0.5 * sx + dpml + 0.5 * Lw, 0, 0)
flux = sim.add_flux(
fcen, 0, 1,
mp.FluxRegion(center=mon_pt, size=mp.Vector3(0, sy - 2 * dpml, 0)))
sim.run(until_after_sources=mp.stop_when_fields_decayed(
50, mp.Ez, src_pt, 1e-9))
incident_coeffs, vgrp, kpoints = sim.get_eigenmode_coefficients(
flux, [1], eig_parity=mp.ODD_Z + mp.EVEN_Y)
incident_flux = mp.get_fluxes(flux)
incident_flux_data = sim.get_flux_data(flux)
sim.reset_meep()
vertices = [
mp.Vector3(-prism_x, half_w1),
mp.Vector3(-half_Lt, half_w1),
mp.Vector3(half_Lt, half_w2),
mp.Vector3(prism_x, half_w2),
mp.Vector3(prism_x, -half_w2),
mp.Vector3(half_Lt, -half_w2),
mp.Vector3(-half_Lt, -half_w1),
mp.Vector3(-prism_x, -half_w1)
]
sim = mp.Simulation(
resolution=resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
geometry=[mp.Prism(vertices, height=mp.inf, material=Si)],
sources=sources,
symmetries=symmetries)
refl_flux = sim.add_flux(
fcen, 0, 1,
mp.FluxRegion(center=mon_pt, size=mp.Vector3(0, sy - 2 * dpml, 0)))
sim.load_minus_flux_data(refl_flux, incident_flux_data)
sim.run(until_after_sources=mp.stop_when_fields_decayed(
50, mp.Ez, src_pt, 1e-9))
coeffs, vgrp, kpoints = sim.get_eigenmode_coefficients(
refl_flux, [1], eig_parity=mp.ODD_Z + mp.EVEN_Y)
taper_flux = mp.get_fluxes(refl_flux)
self.assertAlmostEqual(abs(coeffs[0, 0, 1])**2 /
abs(incident_coeffs[0, 0, 0])**2,
-taper_flux[0] / incident_flux[0],
places=4)
wvl_min = 0.400
wvl_max = 0.700
frq_min = 1 / wvl_max
frq_max = 1 / wvl_min
frq_cen = 0.5 * (frq_min + frq_max)
dfrq = frq_max - frq_min
nfrq = 100
Material = Au
resolution = 300
dpml = 0.11
pml_layers = [
mp.PML(dpml, direction=mp.X, side=mp.High),
mp.Absorber(dpml, direction=mp.X, side=mp.Low)
]
if (k == mp.Ey):
symmetries = [mp.Mirror(mp.Y, phase=-1)]
else:
symmetries = [mp.Mirror(mp.Y)]
celly = (spacing_thickness + block_thicknessy)
cellx = block_thicknessx + 2 * dpml + 2 * offsetx
sources = [
mp.Source(mp.GaussianSource(frq_cen,
fwidth=dfrq,
is_integrated=True),
center=mp.Vector3(-0.5 * cellx + dpml + 0.01),
size=mp.Vector3(0, celly),
component=k)
]
def main(args):
resolution = 20 # pixels/um
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 = args.N # number of holes on either side of defect
sy = args.sy # 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)
blk = mp.Block(size=mp.Vector3(mp.inf, w, mp.inf),
material=mp.Medium(epsilon=eps))
geometry = [blk]
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(1.0)]
fcen = args.fcen # pulse center frequency
df = args.df # pulse frequency width
src = [
mp.Source(mp.GaussianSource(fcen, fwidth=df),
component=mp.Ey,
center=mp.Vector3(-0.5 * sx + dpml),
size=mp.Vector3(0, w))
]
sym = [mp.Mirror(mp.Y, phase=-1)]
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
boundary_layers=pml_layers,
sources=src,
symmetries=sym,
resolution=resolution)
freg = mp.FluxRegion(center=mp.Vector3(0.5 * sx - dpml - 0.5),
size=mp.Vector3(0, 2 * w))
nfreq = 500 # number of frequencies at which to compute flux
# transmitted flux
trans = sim.add_flux(fcen, df, nfreq, freg)
vol = mp.Volume(mp.Vector3(0), size=mp.Vector3(sx))
plt.figure(dpi=150)
sim.plot2D()
#plt.show()
plt.savefig('2Dstructure.png')
sim.run(mp.at_beginning(mp.output_epsilon),
mp.during_sources(
mp.in_volume(
vol,
mp.to_appended("hz-slice",
mp.at_every(0.4, mp.output_hfield_z)))),
until_after_sources=mp.stop_when_fields_decayed(
50, mp.Ey, mp.Vector3(0.5 * sx - dpml - 0.5), 1e-3))
sim.display_fluxes(trans) # print out the flux spectrum
def test_1d_with_symmetry(self):
self._test_1d([mp.Mirror(mp.X)])
def run_test(self, nfreqs):
eps = 13
w = 1.2
r = 0.36
d = 1.4
N = 3
sy = 6
pad = 2
dpml = 1
sx = 2 * (pad + dpml + N) + d - 1
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 = 10
fcen = 0.25
df = 0.2
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 if nfreqs == 1 else 0.1, nfreqs,
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=200)
d2 = 20
h = 4
vol = mp.Volume(mp.Vector3(0, (0.5 * w) + d2 + (0.5 * h)),
size=mp.Vector3(sx - 2 * dpml, h))
result = sim.get_farfields(nearfield, resolution, where=vol)
fname = 'cavity-farfield.h5' if nfreqs == 1 else 'cavity-farfield-4-freqs.h5'
ref_file = os.path.join(self.data_dir, fname)
with h5py.File(ref_file, 'r') as f:
# Get reference data into memory
ref_ex = mp.complexarray(f['ex.r'][()], f['ex.i'][()])
ref_ey = mp.complexarray(f['ey.r'][()], f['ey.i'][()])
ref_ez = mp.complexarray(f['ez.r'][()], f['ez.i'][()])
ref_hx = mp.complexarray(f['hx.r'][()], f['hx.i'][()])
ref_hy = mp.complexarray(f['hy.r'][()], f['hy.i'][()])
ref_hz = mp.complexarray(f['hz.r'][()], f['hz.i'][()])
np.testing.assert_allclose(ref_ex, result['Ex'])
np.testing.assert_allclose(ref_ey, result['Ey'])
np.testing.assert_allclose(ref_ez, result['Ez'])
np.testing.assert_allclose(ref_hx, result['Hx'])
np.testing.assert_allclose(ref_hy, result['Hy'])
np.testing.assert_allclose(ref_hz, result['Hz'])
def test_poynting_theorem(self):
"""Unit test for near-to-far field transformation in 2d.
Verifies that the Poynting flux of an Ez-polarized point
dipole source in vacuum is independent of the shape of the
enclosing measurement box due to Poynting's theorem by
considering three arrangements:
(1) bounding box of thenear fields,
(2) bounding circle of the far fields, and
(3) bounding box of the far fields.
"""
resolution = 50
sxy = 4
dpml = 1
cell = mp.Vector3(sxy + 2 * dpml, sxy + 2 * dpml)
pml_layers = mp.PML(dpml)
fcen = 1.0
df = 0.4
sources = [
mp.Source(src=mp.GaussianSource(fcen, fwidth=df),
center=mp.Vector3(),
component=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, mp.Ez, mp.Vector3(), 1e-8))
near_flux = mp.get_fluxes(flux_box)[0]
r = 1000 / fcen # radius of far field circle
Pr = self.radial_flux(sim, nearfield_box, r)
far_flux_circle = 4 * np.sum(Pr) * 0.5 * np.pi * r / len(Pr)
rr = 20 / fcen # length of far-field square box
res_far = 20 # resolution of far-field square box
far_flux_square = (nearfield_box.flux(
mp.Y, mp.Volume(center=mp.Vector3(y=0.5 * rr),
size=mp.Vector3(rr)), res_far)[0] -
nearfield_box.flux(
mp.Y,
mp.Volume(center=mp.Vector3(y=-0.5 * rr),
size=mp.Vector3(rr)), res_far)[0] +
nearfield_box.flux(
mp.X,
mp.Volume(center=mp.Vector3(0.5 * rr),
size=mp.Vector3(y=rr)), res_far)[0] -
nearfield_box.flux(
mp.X,
mp.Volume(center=mp.Vector3(-0.5 * rr),
size=mp.Vector3(y=rr)), res_far)[0])
print("flux:, {:.6f}, {:.6f}, {:.6f}".format(near_flux,
far_flux_circle,
far_flux_square))
self.assertAlmostEqual(near_flux, far_flux_circle, places=2)
self.assertAlmostEqual(far_flux_circle, far_flux_square, places=2)
self.assertAlmostEqual(far_flux_square, near_flux, places=2)
def main(args):
resolution = 30
nSi = 3.45
Si = mp.Medium(index=nSi)
dpml = 1.0
sx = 5
sy = 3
cell = mp.Vector3(sx + 2 * dpml, sy + 2 * dpml)
pml_layers = mp.PML(dpml)
a = 1.0 # waveguide width
s = args.s # waveguide separation distance
geometry = [
mp.Block(center=mp.Vector3(-0.5 * (s + a)),
size=mp.Vector3(a, a, mp.inf),
material=Si),
mp.Block(center=mp.Vector3(0.5 * (s + a)),
size=mp.Vector3(a, a, mp.inf),
material=Si)
]
xodd = args.xodd
symmetries = [
mp.Mirror(mp.X, phase=-1.0 if xodd else 1.0),
mp.Mirror(mp.Y, phase=-1.0)
]
beta = 0.5
k_point = mp.Vector3(z=beta)
fcen = 0.22
df = 0.06
sources = [
mp.Source(src=mp.GaussianSource(fcen, fwidth=df),
component=mp.Ey,
center=mp.Vector3(-0.5 * (s + a)),
size=mp.Vector3(a, a)),
mp.Source(src=mp.GaussianSource(fcen, fwidth=df),
component=mp.Ey,
center=mp.Vector3(0.5 * (s + a)),
size=mp.Vector3(a, a),
amplitude=-1.0 if xodd else 1.0)
]
sim = mp.Simulation(resolution=resolution,
cell_size=cell,
boundary_layers=[pml_layers],
geometry=geometry,
symmetries=symmetries,
k_point=k_point,
sources=sources,
dimensions=3)
h = mp.Harminv(mp.Ey, mp.Vector3(0.5 * (s + a)), fcen, df)
sim.run(mp.after_sources(h), until_after_sources=200)
f = h.modes[0].freq
print("freq:, {}, {}".format(s, f))
sim.reset_meep()
new_sources = [
mp.EigenModeSource(src=mp.GaussianSource(f, fwidth=df),
component=mp.Ey,
size=mp.Vector3(a, a),
center=mp.Vector3(-0.5 * (s + a)),
eig_kpoint=k_point,
eig_match_freq=True,
eig_parity=mp.ODD_Y),
mp.EigenModeSource(src=mp.GaussianSource(f, fwidth=df),
component=mp.Ey,
size=mp.Vector3(a, a),
center=mp.Vector3(0.5 * (s + a)),
eig_kpoint=k_point,
eig_match_freq=True,
eig_parity=mp.ODD_Y,
amplitude=-1.0 if xodd else 1.0)
]
sim.change_sources(new_sources)
flx_reg = mp.FluxRegion(direction=mp.Z,
center=mp.Vector3(),
size=mp.Vector3(1.2 * (2 * a + s), 1.2 * a))
wvg_pwr = sim.add_flux(f, 0, 1, flx_reg)
frc_reg1 = mp.ForceRegion(mp.Vector3(0.5 * s),
mp.X,
weight=1.0,
size=mp.Vector3(y=a))
frc_reg2 = mp.ForceRegion(mp.Vector3(0.5 * s + a),
mp.X,
weight=-1.0,
size=mp.Vector3(y=a))
wvg_force = sim.add_force(f, 0, 1, frc_reg1, frc_reg2)
runtime = 5000
sim.run(until_after_sources=runtime)
sim.display_fluxes(wvg_pwr)
sim.display_forces(wvg_force)
def grating(gp, gh, gdc, oddz):
sx = dpml + dsub + gh + dpad + dpml
sy = gp
cell_size = mp.Vector3(sx, sy, 0)
pml_layers = [mp.PML(thickness=dpml, direction=mp.X)]
src_pt = mp.Vector3(-0.5 * sx + dpml + 0.5 * dsub, 0, 0)
sources = [
mp.Source(mp.GaussianSource(fcen, fwidth=df),
component=mp.Ez if oddz else mp.Hz,
center=src_pt,
size=mp.Vector3(0, sy, 0))
]
symmetries = [mp.Mirror(mp.Y, phase=+1 if oddz else -1)]
sim = mp.Simulation(resolution=resolution,
cell_size=cell_size,
boundary_layers=pml_layers,
k_point=k_point,
default_material=glass,
sources=sources,
symmetries=symmetries)
mon_pt = mp.Vector3(0.5 * sx - dpml - 0.5 * dpad, 0, 0)
flux_mon = sim.add_flux(
fcen, df, nfreq, mp.FluxRegion(center=mon_pt,
size=mp.Vector3(0, sy, 0)))
sim.run(until_after_sources=100)
input_flux = mp.get_fluxes(flux_mon)
sim.reset_meep()
geometry = [
mp.Block(material=glass,
size=mp.Vector3(dpml + dsub, mp.inf, mp.inf),
center=mp.Vector3(-0.5 * sx + 0.5 * (dpml + dsub), 0, 0)),
mp.Block(material=glass,
size=mp.Vector3(gh, gdc * gp, mp.inf),
center=mp.Vector3(-0.5 * sx + dpml + dsub + 0.5 * gh, 0, 0))
]
sim = mp.Simulation(resolution=resolution,
cell_size=cell_size,
boundary_layers=pml_layers,
geometry=geometry,
k_point=k_point,
sources=sources,
symmetries=symmetries)
mode_mon = sim.add_flux(
fcen, df, nfreq, mp.FluxRegion(center=mon_pt,
size=mp.Vector3(0, sy, 0)))
sim.run(until_after_sources=300)
freqs = mp.get_eigenmode_freqs(mode_mon)
res = sim.get_eigenmode_coefficients(
mode_mon, [1],
eig_parity=mp.ODD_Z + mp.EVEN_Y if oddz else mp.EVEN_Z + mp.ODD_Y)
coeffs = res.alpha
mode_wvl = [1 / freqs[nf] for nf in range(nfreq)]
mode_tran = [
abs(coeffs[0, nf, 0])**2 / input_flux[nf] for nf in range(nfreq)
]
mode_phase = [np.angle(coeffs[0, nf, 0]) for nf in range(nfreq)]
return mode_wvl, mode_tran, mode_phase
# The source will now be the usual Gaussian pulse centered at `fcen`, located at one edge of the cell just outside the PML, at `x = - 0.5 * sx + dpml`. Ideally, we would excite exactly the fundamental mode of the waveguide, but it is good enough to just excite it with a line source. Moreover, since we are interested in the $P$ polarization (electric field in the plane), we will excite it with a $J_y$ current source (transverse to the propagation direction), which is specified as $E_y$:
# In[8]:
src = [
mp.Source(mp.GaussianSource(fcen, fwidth=df),
component=mp.Ey,
center=mp.Vector3(-0.5 * sx + dpml),
size=mp.Vector3(0, w))
]
# The structure has mirror symmetry planes through the $X$ and $Y$ axes. The source breaks the mirror symmetry through the $Y$ axis, but we still have odd mirror symmetry through the $Z$ axis:
# In[9]:
sym = [mp.Mirror(mp.Y, phase=-1)]
# Note that we specify the plane by its normal, the $Y$ direction. See also Exploiting Symmetry. Putting all these objects together via the `Simulation` object:
# In[10]:
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
boundary_layers=pml_layers,
sources=src,
symmetries=sym,
resolution=resolution)
# We need to compute the flux spectrum at the other end of the computational cell, after the holes but before the PML:
# In[11]:
def main(args):
resolution = 20 # pixels/unit length (1 um)
h = args.hh
w = args.w
a = args.a
d = args.d
N = args.N
N = N + 1
nSi = 3.45
Si = mp.Medium(index=nSi)
nSiO2 = 1.45
SiO2 = mp.Medium(index=nSiO2)
sxy = 16
sz = 4
cell_size = mp.Vector3(sxy, sxy, sz)
geometry = []
# rings of Bragg grating
for n in range(N,0,-1):
geometry.append(mp.Cylinder(material=Si, center=mp.Vector3(0,0,0), radius=n*a, height=h))
geometry.append(mp.Cylinder(material=mp.air, center=mp.Vector3(0,0,0), radius=n*a-d, height=h))
# remove left half of Bragg grating rings to form semi circle
geometry.append(mp.Block(material=mp.air, center=mp.Vector3(-0.5*N*a,0,0), size=mp.Vector3(N*a,2*N*a,h)))
geometry.append(mp.Cylinder(material=Si, center=mp.Vector3(0,0,0), radius=a-d, height=h))
# angle sides of Bragg grating
# rotation angle of sides relative to Y axis (degrees)
rot_theta = -1*math.radians(args.rot_theta)
pvec = mp.Vector3(0, 0.5*w, 0)
cvec = mp.Vector3(-0.5*N*a, 0.5*N*a+0.5*w, 0)
rvec = cvec-pvec
rrvec = rvec.rotate(mp.Vector3(0,0,1), rot_theta)
geometry.append(mp.Block(material=mp.air, center=pvec+rrvec, size=mp.Vector3(N*a,N*a,h),
e1=mp.Vector3(0.9396926207859084,-0.3420201433256687,0),
e2=mp.Vector3(0.3420201433256687,0.9396926207859084,0),
e3=mp.Vector3(0,0,1)))
pvec = mp.Vector3(0, -0.5*w, 0)
cvec = mp.Vector3(-0.5*N*a, -1*(0.5*N*a+0.5*w), 0)
rvec = cvec-pvec
rrvec = rvec.rotate(mp.Vector3(0,0,1), -1*rot_theta)
geometry.append(mp.Block(material=mp.air, center=pvec+rrvec, size=mp.Vector3(N*a,N*a,h),
e1=mp.Vector3(0.9396926207859084,0.3420201433256687,0),
e2=mp.Vector3(-0.3420201433256687,0.9396926207859084,0),
e3=mp.Vector3(0,0,1)))
# input waveguide
geometry.append(mp.Block(material=mp.air, center=mp.Vector3(-0.25*sxy,0.5*w+0.5*a,0), size=mp.Vector3(0.5*sxy,a,h)))
geometry.append(mp.Block(material=mp.air, center=mp.Vector3(-0.25*sxy,-1*(0.5*w+0.5*a),0), size=mp.Vector3(0.5*sxy,a,h)))
geometry.append(mp.Block(material=Si, center=mp.Vector3(-0.25*sxy,0,0), size=mp.Vector3(0.5*sxy,w,h)))
# substrate
geometry.append(mp.Block(material=SiO2, center=mp.Vector3(0,0,-0.5*sz+0.25*(sz-h)), size=mp.Vector3(mp.inf,mp.inf,0.5*(sz-h))))
dpml = 1.0
boundary_layers = [ mp.PML(dpml) ]
# mode frequency
fcen = 1/1.55
sources = [ mp.EigenModeSource(src=mp.GaussianSource(fcen, fwidth=0.2*fcen),
component=mp.Ey,
size=mp.Vector3(0,sxy-2*dpml,sz-2*dpml),
center=mp.Vector3(-0.5*sxy+dpml,0,0),
eig_match_freq=True,
eig_parity=mp.ODD_Y,
eig_kpoint=mp.Vector3(1.5,0,0),
eig_resolution=32) ]
symmetries = [ mp.Mirror(mp.Y,-1) ]
sim = mp.Simulation(resolution=resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
geometry=geometry,
sources=sources,
dimensions=3,
symmetries=symmetries)
nearfield = sim.add_near2far(fcen, 0, 1, mp.Near2FarRegion(mp.Vector3(0,0,0.5*sz-dpml), size=mp.Vector3(sxy-2*dpml,sxy-2*dpml,0)))
sim.run(until_after_sources=mp.stop_when_fields_decayed(50, mp.Ey, mp.Vector3(), 1e-6))
r = 1000 * (1 / 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, mp.Vector3(r * math.cos(math.pi * (n / npts)), 0, r * math.sin(math.pi * (n / npts))))
print("farfield: {}, {}, ".format(n, math.pi * n / npts), end='')
print(", ".join([str(f).strip('()').replace('j', 'i') for f in ff]))
def simulate_metalens(metalens):
# Setup the MEEP objects
cell = mp.Vector3(metalens['sim_cell_width'], metalens['sim_cell_height'])
# All around the simulation cell
pml_layers = [mp.PML(metalens['pml_width'])]
# Set up the sources
sources = [
mp.Source(src=mp.ContinuousSource(wavelength=metalens['wavelength'],
width=metalens['source_width']),
component=mp.Ez,
center=mp.Vector3(0, metalens['source_coordinate']),
size=mp.Vector3(2 * metalens['ws'], 0),
amp_func=out_of_plane_dip_amp_func_Ez(metalens)),
mp.Source(src=mp.ContinuousSource(wavelength=metalens['wavelength'],
width=metalens['source_width']),
component=mp.Hx,
center=mp.Vector3(0, metalens['source_coordinate']),
size=mp.Vector3(2 * metalens['ws'], 0),
amp_func=out_of_plane_dip_amp_func_Hx(metalens))
]
# Set up the symmetries
syms = []
if metalens['x_mirror_symmetry']:
syms.append(mp.Mirror(mp.X))
sim = mp.Simulation(cell_size=cell,
boundary_layers=pml_layers,
geometry=metalens['geometry'],
force_complex_fields=metalens['complex_fields'],
symmetries=syms,
sources=sources,
resolution=metalens['resolution'])
start_time = time.time()
metalens['run_date'] = (
datetime.datetime.now().strftime("%b %d %Y at %H:%M:%S"))
mp.quiet(metalens['quiet'])
sim.init_sim()
# Branch if saving for making an animation
if metalens['save_output']:
sim.run(mp.to_appended(
"ez-{sim_id}".format(**metalens),
mp.at_every(metalens['simulation_time'] / 1000.,
mp.output_efield_z)),
until=metalens['simulation_time'])
else:
sim.run(until=metalens['simulation_time'])
# Compute the clock run time and grab the fields
metalens['array_metadata'] = sim.get_array_metadata()
metalens['run_time_in_s'] = time.time() - start_time
metalens['fields'] = {
'Ez': sim.get_array(component=mp.Ez).transpose(),
'Hx': sim.get_array(component=mp.Hx).transpose(),
'Hy': sim.get_array(component=mp.Hy).transpose()
}
metalens['eps'] = sim.get_epsilon().transpose()
# Dump the result to disk
if metalens['log_to_pkl'][0]:
if metalens['log_to_pkl'][1] == '':
pkl_fname = '%smetalens-%s.pkl' % (datadir, metalens['sim_id'])
else:
pkl_fname = metalens['log_to_pkl'][1]
print(pkl_fname)
pickle.dump(metalens, open(pkl_fname, 'wb'))
return metalens
def test_transmission_spectrum(self):
expected = [
(0.15, 7.218492264696595e-6),
(0.1504008016032064, 6.445696315927592e-6),
(0.1508016032064128, 5.140949243632777e-6),
(0.15120240480961922, 3.6159747936427164e-6),
(0.15160320641282563, 2.263940553705969e-6),
(0.15200400801603203, 1.4757165844336744e-6),
(0.15240480961923844, 1.5491803919142815e-6),
(0.15280561122244485, 2.612053246626972e-6),
(0.15320641282565126, 4.577504371188737e-6),
(0.15360721442885766, 7.1459089162998185e-6),
(0.15400801603206407, 9.856622013418823e-6),
(0.15440881763527048, 1.2182309227954296e-5),
(0.1548096192384769, 1.3647726444709649e-5),
(0.1552104208416833, 1.3947420613633674e-5),
(0.1556112224448897, 1.303466755716231e-5),
(0.1560120240480961, 1.115807915037775e-5),
(0.15641282565130252, 8.832335196969796e-6),
(0.15681362725450892, 6.743645773127985e-6),
(0.15721442885771533, 5.605913756087576e-6),
(0.15761523046092174, 5.996668564026961e-6),
(0.15801603206412815, 8.209400611614078e-6),
(0.15841683366733456, 1.2158641936828497e-5),
(0.15881763527054096, 1.73653230513453e-5),
(0.15921843687374737, 2.303382576477893e-5),
(0.15961923847695378, 2.821180350795834e-5),
(0.1600200400801602, 3.200359292911769e-5),
(0.1604208416833666, 3.3792624373001934e-5),
(0.160821643286573, 3.342171394788991e-5),
(0.1612224448897794, 3.1284866146526904e-5),
(0.16162324649298582, 2.830022088581398e-5),
(0.16202404809619222, 2.5758413657344014e-5),
(0.16242484969939863, 2.506899997971769e-5),
(0.16282565130260504, 2.7453508915303887e-5),
(0.16322645290581145, 3.365089813497114e-5),
(0.16362725450901786, 4.370486834112e-5),
(0.16402805611222426, 5.689050715055283e-5),
(0.16442885771543067, 7.181133157470506e-5),
(0.16482965931863708, 8.666168027415369e-5),
(0.16523046092184349, 9.961094123261317e-5),
(0.1656312625250499, 1.0923388232657953e-4),
(0.1660320641282563, 1.1489334204708105e-4),
(0.1664328657314627, 1.1698318060032011e-4),
(0.16683366733466912, 1.169621456132733e-4),
(0.16723446893787552, 1.1714995241571987e-4),
(0.16763527054108193, 1.2030783847222252e-4),
(0.16803607214428834, 1.2907652919660887e-4),
]
self.sim.sources = [
mp.Source(mp.GaussianSource(self.fcen, fwidth=self.df),
mp.Ey,
mp.Vector3(self.dpml + (-0.5 * self.sx)),
size=mp.Vector3(0, self.w))
]
self.sim.symmetries = [mp.Mirror(mp.Y, phase=-1)]
freg = mp.FluxRegion(center=mp.Vector3((0.5 * self.sx) - self.dpml -
0.5),
size=mp.Vector3(0, 2 * self.w))
trans = self.sim.add_flux(self.fcen,
self.df,
self.nfreq,
freg,
decimation_factor=1)
self.sim.run(until_after_sources=mp.stop_when_fields_decayed(
50, mp.Ey, mp.Vector3((0.5 * self.sx) - self.dpml - 0.5, 0), 1e-1))
res = zip(mp.get_flux_freqs(trans), mp.get_fluxes(trans))
tol = 1e-8 if mp.is_single_precision() else 1e-10
for e, r in zip(expected, res):
self.assertClose(e, r, epsilon=tol)
def test_array_metadata(self):
resolution = 25
n = 3.4
w = 1
r = 1
pad = 4
dpml = 2
sxy = 2 * (r + w + pad + dpml)
cell_size = mp.Vector3(sxy, sxy)
nonpml_vol = mp.Volume(mp.Vector3(),
size=mp.Vector3(sxy - 2 * dpml, sxy - 2 * dpml))
geometry = [
mp.Cylinder(radius=r + w, material=mp.Medium(index=n)),
mp.Cylinder(radius=r)
]
fcen = 0.118
df = 0.08
symmetries = [mp.Mirror(mp.X, phase=-1), mp.Mirror(mp.Y, phase=+1)]
pml_layers = [mp.PML(dpml)]
# CW source
src = [
mp.Source(mp.ContinuousSource(fcen, fwidth=df), mp.Ez,
mp.Vector3(r + 0.1)),
mp.Source(mp.ContinuousSource(fcen, fwidth=df),
mp.Ez,
mp.Vector3(-(r + 0.1)),
amplitude=-1)
]
sim = mp.Simulation(cell_size=cell_size,
geometry=geometry,
sources=src,
resolution=resolution,
force_complex_fields=True,
symmetries=symmetries,
boundary_layers=pml_layers)
sim.init_sim()
sim.solve_cw(1e-5 if mp.is_single_precision() else 1e-6, 1000, 10)
def electric_energy(r, ez, eps):
return np.real(eps * np.conj(ez) * ez)
def vec_func(r):
return r.x**2 + 2 * r.y**2
electric_energy_total = sim.integrate_field_function(
[mp.Ez, mp.Dielectric], electric_energy, nonpml_vol)
electric_energy_max = sim.max_abs_field_function(
[mp.Ez, mp.Dielectric], electric_energy, nonpml_vol)
vec_func_total = sim.integrate_field_function([], vec_func, nonpml_vol)
cw_modal_volume = (electric_energy_total /
electric_energy_max) * vec_func_total
sim.reset_meep()
# pulsed source
src = [
mp.Source(mp.GaussianSource(fcen, fwidth=df), mp.Ez,
mp.Vector3(r + 0.1)),
mp.Source(mp.GaussianSource(fcen, fwidth=df),
mp.Ez,
mp.Vector3(-(r + 0.1)),
amplitude=-1)
]
sim = mp.Simulation(cell_size=cell_size,
geometry=geometry,
k_point=mp.Vector3(),
sources=src,
resolution=resolution,
symmetries=symmetries,
boundary_layers=pml_layers)
dft_obj = sim.add_dft_fields([mp.Ez], fcen, 0, 1, where=nonpml_vol)
sim.run(until_after_sources=100)
Ez = sim.get_dft_array(dft_obj, mp.Ez, 0)
(X, Y, Z, W) = sim.get_array_metadata(dft_cell=dft_obj)
Eps = sim.get_array(vol=nonpml_vol, component=mp.Dielectric)
EpsE2 = np.real(Eps * np.conj(Ez) * Ez)
xm, ym = np.meshgrid(X, Y)
vec_func_sum = np.sum(W * (xm**2 + 2 * ym**2))
pulse_modal_volume = np.sum(W * EpsE2) / np.max(EpsE2) * vec_func_sum
tol = 5e-2 if mp.is_single_precision() else 1e-2
self.assertClose(cw_modal_volume / pulse_modal_volume,
1.0,
epsilon=tol)
]
resolution = 200
wvl = 825 / 1000 #convert args.wvl from nm to μm
fcen = 1 / wvl
df = 0
nfreq = 1
print("wavelength =", wvl, "μm")
print("center frequency =", fcen, "1/μm")
source = [
mp.Source(mp.GaussianSource(fcen, df, nfreq),
component=mp.Ey,
center=mp.Vector3(0, -0.705, 0))
]
symmetries = [mp.Mirror(mp.X), mp.Mirror(mp.Z)]
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
sources=source,
resolution=resolution,
boundary_layers=pml_layers)
pt = mp.Vector3(0, -0.705, 0)
sim.run(mp.dft_ldos(fcen, 0, nfreq),
until_after_sources=mp.stop_when_fields_decayed(20, mp.Ey, pt, 1e-3))
eps_data = sim.get_array(center=mp.Vector3(),
size=cell,
component=mp.Dielectric)
ey_data = sim.get_array(center=mp.Vector3(), size=cell, component=mp.Ey)
def main(args):
resolution = args.res
w1 = 1 # width of waveguide 1
w2 = args.w2 # width of waveguide 2
Lw = 10 # length of waveguide 1 and 2
Lt = args.Lt # taper length
Si = mp.Medium(epsilon=12.0)
dair = 3.0
dpml = 3.0
sx = dpml + Lw + Lt + Lw + dpml
sy = dpml + dair + w2 + dair + dpml
cell_size = mp.Vector3(sx, sy, 0)
geometry = [
mp.Block(material=Si,
center=mp.Vector3(0, 0, 0),
size=mp.Vector3(mp.inf, w1, mp.inf)),
mp.Block(material=Si,
center=mp.Vector3(0.5 * sx - 0.5 * (Lt + Lw + dpml), 0, 0),
size=mp.Vector3(Lt + Lw + dpml, w2, mp.inf))
]
# form linear taper
hh = w2
ww = 2 * Lt
# taper angle (CCW, relative to +X axis)
rot_theta = math.atan(0.5 * (w2 - w1) / Lt)
pvec = mp.Vector3(-0.5 * sx + dpml + Lw, 0.5 * w1, 0)
cvec = mp.Vector3(-0.5 * sx + dpml + Lw + 0.5 * ww, 0.5 * hh + 0.5 * w1, 0)
rvec = cvec - pvec
rrvec = rvec.rotate(mp.Vector3(0, 0, 1), rot_theta)
geometry.append(
mp.Block(material=mp.air,
center=pvec + rrvec,
size=mp.Vector3(ww, hh, mp.inf),
e1=mp.Vector3(1, 0, 0).rotate(mp.Vector3(0, 0, 1), rot_theta),
e2=mp.Vector3(0, 1, 0).rotate(mp.Vector3(0, 0, 1), rot_theta),
e3=mp.Vector3(0, 0, 1)))
pvec = mp.Vector3(-0.5 * sx + dpml + Lw, -0.5 * w1, 0)
cvec = mp.Vector3(-0.5 * sx + dpml + Lw + 0.5 * ww, -(0.5 * hh + 0.5 * w1),
0)
rvec = cvec - pvec
rrvec = rvec.rotate(mp.Vector3(0, 0, 1), -rot_theta)
geometry.append(
mp.Block(material=mp.air,
center=pvec + rrvec,
size=mp.Vector3(ww, hh, mp.inf),
e1=mp.Vector3(1, 0, 0).rotate(mp.Vector3(0, 0, 1),
-rot_theta),
e2=mp.Vector3(0, 1, 0).rotate(mp.Vector3(0, 0, 1),
-rot_theta),
e3=mp.Vector3(0, 0, 1)))
boundary_layers = [mp.PML(dpml)]
# mode frequency
fcen = 0.15
sources = [
mp.EigenModeSource(src=mp.GaussianSource(fcen, fwidth=0.5 * fcen),
component=mp.Ez,
size=mp.Vector3(0, sy - 2 * dpml, 0),
center=mp.Vector3(-0.5 * sx + dpml, 0, 0),
eig_match_freq=True,
eig_parity=mp.ODD_Z,
eig_kpoint=mp.Vector3(0.4, 0, 0),
eig_resolution=32)
]
symmetries = [mp.Mirror(mp.Y, +1)]
sim = mp.Simulation(resolution=resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
geometry=geometry,
sources=sources,
symmetries=symmetries)
xm = -0.5 * sx + dpml + 0.5 * Lw # x-coordinate of monitor
mflux = sim.add_eigenmode(
fcen, 0, 1,
mp.FluxRegion(center=mp.Vector3(xm, 0),
size=mp.Vector3(0, sy - 2 * dpml)))
sim.run(until_after_sources=mp.stop_when_fields_decayed(
50, mp.Ez, mp.Vector3(xm, 0), 1e-10))
bands = [1] # indices of modes for which to compute expansion coefficients
alpha = sim.get_eigenmode_coefficients(mflux, bands)
alpha0Plus = alpha[2 * 0 +
0] # coefficient of forward-traveling fundamental mode
alpha0Minus = alpha[
2 * 0 + 1] # coefficient of backward-traveling fundamental mode
print("refl:, {}, {:.8f}".format(Lt, abs(alpha0Minus)**2))
def main(args):
sx = 8.0 #spatial extent along x including pmls (μm)
sy = 4
sz = 0
dpml = 1.0
cell = mp.Vector3(sx, sy, sz)
pml_layers = [mp.PML(dpml)]
resolution = args.res
wvl = args.wvl #source wavelength
fcen = 1 / wvl #center frequency
df = 0 #frequency bandwidth
nfreq = 1 #number of frequencies
dw = args.dw # slab thickness increment(um)
w_init = args.w_init # initial slab thickness(μm)
n = args.n
w = w_init + n * dw #next slab thicknessw
slab_center_y = 0.5 * w #slab center y coordinate
sfor_y = w + 0.005 #sfor_y = y coordinate of the slit_flux_output_region
s = 0.030 #slit width
print("wavelength =", wvl, "μm")
print("slab size =", w, "μm")
print("center frequency =", fcen, "1/μm")
print("slit_flux_output_region y coordinate =", sfor_y, "μm")
print("slab center y coordinate =", slab_center_y, "μm")
geometry = [
mp.Block(mp.Vector3(mp.inf, w, mp.inf),
center=mp.Vector3(0, slab_center_y),
material=Ag)
]
source = [
mp.Source(mp.GaussianSource(fcen, df, nfreq),
component=mp.Ex,
center=mp.Vector3(0, -0.5 * (sy - 2.1), 0),
size=mp.Vector3(sx - 2.0, 0, 0))
]
symmetries = [mp.Mirror(mp.X), mp.Mirror(mp.Z)]
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
sources=source,
resolution=resolution,
boundary_layers=pml_layers,
filename_prefix='slab_noslit')
sim.use_output_directory()
pt = mp.Vector3(
0, -0.5 * (sy - 2.1), 0
) #point where field intensity is measured (usually at source position)
slab_flux_in_region = mp.FluxRegion(
center=mp.Vector3(0, -0.005, 0),
size=mp.Vector3(sx, 0, 0)) #incident flux monitor 5nm above slab.
slab_flux_in = sim.add_flux(fcen, df, nfreq, slab_flux_in_region)
slab_flux_in_data = sim.get_flux_data(
slab_flux_in) #data are the E and H fields used to calculate S=ExH
slab_flux_out_region = mp.FluxRegion(
center=mp.Vector3(0, sfor_y, 0),
size=mp.Vector3(sx, 0, 0)) #trans flux monitor 5nm below slab.
slab_flux_out = sim.add_flux(fcen, df, nfreq, slab_flux_out_region)
slab_flux_out_data = sim.get_flux_data(slab_flux_out)
sim.run(mp.dft_ldos(fcen, df, nfreq),
mp.at_beginning(mp.output_epsilon),
until_after_sources=mp.stop_when_fields_decayed(
10, mp.Hz, pt, 1e-5))
slab_flux_input = []
slab_flux_output = []
slab_flux_input = mp.get_fluxes(slab_flux_in)
slab_flux_output = mp.get_fluxes(slab_flux_out)
print('incident flux slab =', slab_flux_input, ' ',
'transmitted flux slab =', slab_flux_output, ' ',
'normed transmitted flux=',
np.divide(slab_flux_output, slab_flux_input))
eps_data_slab = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Dielectric)
ex_data_slab = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Ex)
hz_data_slab = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Hz)
sim.reset_meep()
geometry = [
mp.Block(mp.Vector3(mp.inf, w, mp.inf),
center=mp.Vector3(0, 0.5 * (w)),
material=Ag),
mp.Block(mp.Vector3(s, w, 0),
center=mp.Vector3(0, 0.5 * (w), 0),
material=mp.Medium(epsilon=1))
]
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
sources=source,
resolution=resolution,
boundary_layers=pml_layers,
filename_prefix="slab_slit")
sim.use_output_directory()
slit_flux_in_region = mp.FluxRegion(center=mp.Vector3(0, -0.005, 0),
size=mp.Vector3(
sx, 0,
0)) #same as slab_flux_in_region
slit_flux_in = sim.add_flux(fcen, df, nfreq, slit_flux_in_region)
slit_flux_in_data = sim.get_flux_data(slit_flux_in)
slit_flux_out_region = mp.FluxRegion(center=mp.Vector3(0, w + 0.005, 0),
size=mp.Vector3(
sx, 0,
0)) #same as slab_flux_out_region
slit_flux_out = sim.add_flux(fcen, df, nfreq, slit_flux_out_region)
slit_flux_out_data = sim.get_flux_data(slit_flux_out)
sim.load_minus_flux_data(slit_flux_out, slab_flux_out_data)
#subract transmitted slab flux data (slab_flux_out_data) from slit_flux_out. This is a correction so that flux only
#from the slit is registered in slit_flux_out.
sim.run(mp.dft_ldos(fcen, 0, nfreq),
mp.at_beginning(mp.output_epsilon),
until_after_sources=mp.stop_when_fields_decayed(
10, mp.Hz, pt, 1e-4))
slit_flux_input = []
slit_flux_output = []
slit_flux_input = mp.get_fluxes(slit_flux_in)
slit_flux_output = mp.get_fluxes(slit_flux_out)
print('slit flux net =', slit_flux_output, ' ', 'slit_flux_normed =',
np.divide(slit_flux_output, slab_flux_input))
eps_data_slit = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Dielectric)
ex_data_slit = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Ex)
hz_data_slit = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Hz)
slabFlux = []
slabFlux = np.append(slabFlux, slab_flux_input)
slitFlux = []
slitFlux = np.append(slitFlux, slit_flux_output)
fracFlux = np.divide(slitFlux, slabFlux)
print('normalised slit flux,',
end=" ") #suppress the print newline function with end=" "
np.savetxt(
sys.stdout, fracFlux, fmt='%7.5f'
) #print to stdout transmitted slit flux normalised to input flux.
print('slab thickness,', end=" ")
print(w)
#-------------------------------- Next three lines ok for data file in mp meep, but writes data np times (np no. processors) in pmp.
#f=open('fracFL.dat','ab')
#np.savetxt(f,fracFl,fmt='%6.5f')
#f.close()
#----------------------------------------------------
eps_data_slit = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Dielectric)
hz_data_slit = sim.get_array(center=mp.Vector3(0, 0, 0),
size=mp.Vector3(sx, sy, sz),
component=mp.Hz)
hz_scat = hz_data_slit - hz_data_slab
def parallel_waveguide(s, xodd):
geometry = [
mp.Block(center=mp.Vector3(-0.5 * (s + a)),
size=mp.Vector3(a, a, mp.inf),
material=Si),
mp.Block(center=mp.Vector3(0.5 * (s + a)),
size=mp.Vector3(a, a, mp.inf),
material=Si)
]
symmetries = [
mp.Mirror(mp.X, phase=-1.0 if xodd else 1.0),
mp.Mirror(mp.Y, phase=-1.0)
]
sources = [
mp.Source(src=mp.GaussianSource(fcen, fwidth=df),
component=mp.Ey,
center=mp.Vector3(-0.5 * (s + a)),
size=mp.Vector3(a, a)),
mp.Source(src=mp.GaussianSource(fcen, fwidth=df),
component=mp.Ey,
center=mp.Vector3(0.5 * (s + a)),
size=mp.Vector3(a, a),
amplitude=-1.0 if xodd else 1.0)
]
sim = mp.Simulation(resolution=resolution,
cell_size=cell,
boundary_layers=pml_layers,
geometry=geometry,
symmetries=symmetries,
k_point=k_point,
sources=sources)
h = mp.Harminv(mp.Ey, mp.Vector3(0.5 * (s + a)), fcen, df)
sim.run(mp.after_sources(h), until_after_sources=200)
f = h.modes[0].freq
print("freq:, {}, {}".format(s, f))
sim.reset_meep()
eig_sources = [
mp.EigenModeSource(src=mp.GaussianSource(f, fwidth=df),
size=mp.Vector3(a, a),
center=mp.Vector3(-0.5 * (s + a)),
direction=mp.Z,
eig_kpoint=k_point,
eig_match_freq=True,
eig_parity=mp.ODD_Y),
mp.EigenModeSource(src=mp.GaussianSource(f, fwidth=df),
size=mp.Vector3(a, a),
center=mp.Vector3(0.5 * (s + a)),
direction=mp.Z,
eig_kpoint=k_point,
eig_match_freq=True,
eig_parity=mp.ODD_Y,
amplitude=-1.0 if xodd else 1.0)
]
sim.change_sources(eig_sources)
flux_reg = mp.FluxRegion(direction=mp.Z,
center=mp.Vector3(),
size=mp.Vector3(1.2 * (2 * a + s), 1.2 * a))
wvg_flux = sim.add_flux(f, 0, 1, flux_reg)
force_reg1 = mp.ForceRegion(mp.Vector3(0.5 * s),
direction=mp.X,
weight=1.0,
size=mp.Vector3(y=a))
force_reg2 = mp.ForceRegion(mp.Vector3(0.5 * s + a),
direction=mp.X,
weight=-1.0,
size=mp.Vector3(y=a))
wvg_force = sim.add_force(f, 0, 1, force_reg1, force_reg2)
sim.run(until_after_sources=500)
flux = mp.get_fluxes(wvg_flux)[0]
force = mp.get_forces(wvg_force)[0]
sim.reset_meep()
return flux, force