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 radiating_base(self, sq_ratio, solve_cw=True):
w = 0.30
s = mp.structure(self.gv, one, mp.pml(self.ymax / 3.0))
f = mp.fields(s)
src = ContinuousSource(w)
f.add_point_source(mp.Ez, src, self.pnt_src_vec)
# let the source reach steady state
if solve_cw:
f.solve_cw(1e-6)
else:
while f.time() < 400:
f.step()
# amp1 and amp2 are of type complex
amp1 = f.get_field(mp.Ez, self.p1)
amp2 = f.get_field(mp.Ez, self.p2)
ratio = abs(amp1) / abs(amp2)
if self.gv.dim == mp.D2:
ratio = ratio**2 # in 2d, decay is ~1/sqrt(r), so square to get 1/r
print("Ratio is {} from ({} {}) and ({} {})".format(
ratio, amp1.real, amp1, amp2.real, amp2))
fail_fmt = "Failed: amp1 = ({}, {}), amp2 = ({}, {})\nabs(amp1/amp2){} = {}, too far from 2.0"
fail_msg = fail_fmt.format(amp1.real, amp1, amp2.real, amp2,
"^2" if sq_ratio else "", ratio)
self.assertTrue(ratio <= 2.12 and ratio >= 1.88, fail_msg)
def __init__(self, thickness,
direction=mp.ALL,
side=mp.ALL,
R_asymptotic=1e-15,
mean_stretch=1.0,
pml_profile=lambda u: u * u):
self.thickness = thickness
self.direction = direction
self.side = side
self.R_asymptotic = R_asymptotic
self.mean_stretch = mean_stretch
self.pml_profile = pml_profile
if direction == mp.ALL and side == mp.ALL:
self.swigobj = mp.pml(thickness, R_asymptotic, mean_stretch)
elif direction == mp.ALL:
self.swigobj = mp.pml(thickness, side, R_asymptotic, mean_stretch)
else:
self.swigobj = mp.pml(thickness, direction, side, R_asymptotic, mean_stretch)
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))
LOG.debug("Meep node %i -Defining structure..." % (self.node_nr))
symmetry_object = Meep.identity()
if (self.symmY):
LOG.debug("Meep node %i -Using y symmetry!" % (self.node_nr))
symmetry_object = Meep.mirror(Meep.Y, self.meepVol)
symmetry_object = symmetry_object * complex(1.0, 0.0)
# When there is a certain PML direction, use that one.
if isinstance(landscape.pml_direction, str):
dirint = 'XYZ'.rfind(str.upper(landscape.pml_direction))
assert dirint <= 0, 'PML direction should be either X, Y or Z'
if dirint == 0: direction = Meep.X
if dirint == 1: direction = Meep.Y
if dirint == 2: direction = Meep.Z
pml = Meep.pml(landscape.pml_thickness, direction)
else:
pml = Meep.pml(landscape.pml_thickness)
self.structure = Meep.structure(self.meepVol,
Meep.EPS,
pml,
symmetry=symmetry_object)
if self.is_nonlinear:
LOG.debug("Meep node %i, setting chi3" % (self.node_nr))
self.chi3 = MeepChi3_2D(landscape.simulation_volume, self.meepVol)
Meep.set_CHI3_Callback(self.chi3.__disown__())
self.structure.set_chi3(CHI3)
LOG.debug("Meep node %i -Defining fields..." % (self.node_nr))
self.meep_fields = Meep.fields(self.structure)
def __init__(self,gridSizeX,gridSizeY,res,f,df,n_freqs = 1000,boundary_conditions = pml(1.0,Y),periodic_directions = [],bloch = vec(0.0,0.0),symmetry_direction = None,symmetry_val = complex(1.0),gridSizeZ = None):
self.gridSizeX = gridSizeX
self.gridSizeY = gridSizeY
self.gridSizeZ = gridSizeZ
self.res = res
self.boundary_conditions = boundary_conditions
self.fluxes = []
self.f = f
self.df = df
self.n_freqs = n_freqs
self.symmetry_direction = symmetry_direction
self.symmetry_val = symmetry_val
self.periodic_directions = periodic_directions
self.bloch = bloch
self.my_source = None
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]))
