def main(args):
n = 3.4 # index of waveguide
w = 1.0 # width of waveguide
r = 1.0 # inner radius of ring
pad = 4 # padding between waveguide and edge of PML
dpml = 2 # thickness of PML
sxy = 2.0 * (r + w + pad + dpml) # cell size
resolution = 10.0
gv = mp.voltwo(sxy, sxy, resolution)
gv.center_origin()
sym = mp.mirror(mp.Y, gv)
# exploit the mirror symmetry in structure+source:
the_structure = mp.structure(gv, dummy_eps, mp.pml(dpml), sym)
# Create a ring waveguide by two overlapping cylinders - later objects
# take precedence over earlier objects, so we put the outer cylinder first.
# and the inner (air) cylinder second.
objects = []
n2 = n * n
dielectric = gm.Medium(epsilon_diag=gm.Vector3(n2, n2, n2))
objects.append(gm.Cylinder(r + w, material=dielectric))
objects.append(gm.Cylinder(r))
mp.set_materials_from_geometry(the_structure, objects)
f = mp.fields(the_structure)
# If we don't want to excite a specific mode symmetry, we can just
# put a single point source at some arbitrary place, pointing in some
# arbitrary direction. We will only look for TM modes (E out of the plane).
fcen = 0.15 # pulse center frequency
df = 0.1
src = GaussianSource(fcen, df)
v = mp.volume(mp.vec(r + 0.1, 0.0), mp.vec(0.0, 0.0))
f.add_volume_source(mp.Ez, src, v)
T = 300.0
stop_time = f.last_source_time() + T
while f.round_time() < stop_time:
f.step()
# TODO: translate call to harminv
# int bands = do_harminv (... Ez, vec3(r+0.1), fcen, df)
# Output fields for one period at the end. (If we output
# at a single time, we might accidentally catch the Ez field
# when it is almost zero and get a distorted view.)
DeltaT = 1.0 / (20 * fcen)
NextOutputTime = f.round_time() + DeltaT
while f.round_time() < 1.0 / fcen:
f.step()
if f.round_time() >= NextOutputTime:
f.output_hdf5(mp.Ez, f.total_volume())
NextOutputTime += DeltaT
def make_fields(self):
if self.gridSizeZ == None:
self.meep_space = voltwo(self.gridSizeX,self.gridSizeY,self.res)
else:
self.meep_space = vol3d(self.gridSizeX,self.gridSizeY,self.gridSizeZ,self.res)
material = epsilon(self.my_structure)
set_EPS_Callback(material.__disown__())
if self.symmetry_direction == None:
sym = identity()
else:
sym = mirror(self.symmetry_direction,self.meep_space)*self.symmetry_val
self.meep_structure = structure(self.meep_space, EPS, self.boundary_conditions,sym)
the_fields = fields(self.meep_structure)
for direc in self.periodic_directions:
the_fields.set_boundary(Low,direc,Periodic)
the_fields.set_boundary(High,direc,Periodic)
the_fields.use_bloch(self.bloch)
if self.my_source is not None:
self.my_source.add_to_fields(the_fields)
for f in self.fluxes:
f.add_to_fields(the_fields)
self.meep_fields = the_fields
return the_fields
def test_radiating_2d(self):
xmax = 8.0
# grid_volume
self.gv = mp.voltwo(xmax, self.ymax, self.a)
self.pnt_src_vec = mp.vec(xmax / 2 - self.dx, self.ymax / 2)
self.p1 = mp.vec(xmax / 2 + 0 * self.dx, self.ymax / 2)
self.p2 = mp.vec(xmax / 2 + 1 * self.dx, self.ymax / 2)
self.radiating_base(True)
def setUp(self):
def dummy_eps(v):
return 1.0
gv = mp.voltwo(16, 16, 10)
gv.center_origin()
sym = mp.mirror(mp.Y, gv)
the_structure = mp.structure(gv, dummy_eps, mp.pml(2), sym)
objects = []
objects.append(Cylinder(1))
mp.set_materials_from_geometry(the_structure, objects)
self.f = mp.fields(the_structure)
self.v = mp.volume(mp.vec(1.1, 0.0), mp.vec(0.0, 0.0))
def setUp(self):
def dummy_eps(v):
return 1.0
gv = mp.voltwo(16, 16, 10)
gv.center_origin()
sym = mp.mirror(mp.Y, gv)
the_structure = mp.structure(gv, dummy_eps, mp.pml(2), sym)
objects = []
objects.append(Cylinder(1))
mp.set_materials_from_geometry(the_structure, objects)
self.f = mp.fields(the_structure)
self.v = mp.volume(mp.vec(1.1, 0.0), mp.vec(0.0, 0.0))
def bend_flux(no_bend):
sx = 16.0 # size of cell in X direction
sy = 32.0 # size of cell in Y direction
pad = 4.0 # padding distance between waveguide and cell edge
w = 1.0 # width of waveguide
resolution = 10 # (set-param! resolution 10)
gv = mp.voltwo(sx, sy, resolution)
gv.center_origin()
the_structure = mp.structure(gv, dummy_eps, mp.pml(1.0))
wvg_ycen = -0.5 * (sy - w - 2.0 * pad) # y center of horiz. wvg
wvg_xcen = 0.5 * (sx - w - 2.0 * pad) # x center of vert. wvg
e1 = gm.Vector3(1.0, 0.0, 0.0)
e2 = gm.Vector3(0.0, 1.0, 0.0)
e3 = gm.Vector3(0.0, 0.0, 1.0)
dielectric = gm.Medium(epsilon_diag=gm.Vector3(12, 12, 12))
if no_bend:
center = gm.Vector3(y=wvg_ycen)
size = gm.Vector3(float('inf'), w, float('inf'))
objects = [
gm.Block(size, e1, e2, e3, material=dielectric, center=center)
]
mp.set_materials_from_geometry(the_structure, objects)
else:
objects = []
center = gm.Vector3(-0.5 * pad, wvg_ycen)
size = gm.Vector3(sx - pad, w, float('inf'))
objects.append(
gm.Block(size, e1, e2, e3, material=dielectric, center=center))
center = gm.Vector3(wvg_xcen, 0.5 * pad)
size = gm.Vector3(w, sy - pad, float('inf'))
objects.append(
gm.Block(size, e1, e2, e3, material=dielectric, center=center))
mp.set_materials_from_geometry(the_structure, objects)
f = mp.fields(the_structure)
fcen = 0.15 # pulse center frequency
df = 0.1
src = GaussianSource(fcen, df)
v = mp.volume(mp.vec(1.0 - 0.5 * sx, wvg_ycen), mp.vec(0.0, w))
f.add_volume_source(mp.Ez, src, v)
f_start = fcen - 0.5 * df
f_end = fcen + 0.5 * df
nfreq = 100 # number of frequencies at which to compute flux
if no_bend:
trans_volume = mp.volume(mp.vec(0.5 * sx - 1.5, wvg_ycen),
mp.vec(0.0, 2.0 * w))
else:
trans_volume = mp.volume(mp.vec(wvg_xcen, 0.5 * sy - 1.5),
mp.vec(2.0 * w, 0.0))
trans_vl = mp.volume_list(trans_volume, mp.Sz)
trans = f.add_dft_flux(trans_vl, f_start, f_end, nfreq)
refl_volume = mp.volume(mp.vec(-0.5 * sx + 1.5, wvg_ycen),
mp.vec(0.0, 2.0 * w))
refl_vl = mp.volume_list(refl_volume, mp.Sz)
refl = f.add_dft_flux(refl_vl, f_start, f_end, nfreq)
dataname = "refl-flux"
if not no_bend:
refl.load_hdf5(f, dataname)
refl.scale_dfts(-1.0)
eval_point = mp.vec(0.5 * sx - 1.5, wvg_ycen) if no_bend else mp.vec(
wvg_xcen, 0.5 * sy - 1.5)
deltaT = 50.0
next_check_time = f.round_time() + deltaT
tol = 1.0e-3
max_abs = 0.0
cur_max = 0.0
done = False
while not done:
f.step()
# manually check fields-decayed condition
absEz = abs(f.get_field(mp.Ez, eval_point))
cur_max = max(cur_max, absEz)
if f.round_time() >= next_check_time:
next_check_time += deltaT
max_abs = max(max_abs, cur_max)
if max_abs > 0.0 and cur_max < tol * max_abs:
done = True
cur_max = 0.0
# printf("%.2e %.2e %.2e %.2e\n",f.round_time(),absEz,max_abs,cur_max)
if no_bend:
refl.save_hdf5(f, dataname)
print("{}\t\t | {}\t\t | {}".format("Time", "trans flux", "refl flux"))
f0 = fcen - 0.5 * df
fstep = df / (nfreq - 1)
trans_flux = trans.flux()
refl_flux = refl.flux()
for nf in range(nfreq):
print("{}\t\t | {}\t\t | {}".format(f0 + nf * fstep, trans_flux[nf],
refl_flux[nf]))
