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import meep as mp
import numpy as np
import matplotlib.pyplot as plt
resolution = 50 # pixels/μm
cell_size = mp.Vector3(14,14)
pml_layers = [mp.PML(thickness=2)]
# rotation angle (in degrees) of waveguide, counter clockwise (CCW) around z-axis
rot_angle = np.radians(20)
w = 1.0 # width of waveguide
geometry = [mp.Block(center=mp.Vector3(),
size=mp.Vector3(mp.inf,w,mp.inf),
e1=mp.Vector3(x=1).rotate(mp.Vector3(z=1), rot_angle),
e2=mp.Vector3(y=1).rotate(mp.Vector3(z=1), rot_angle),
material=mp.Medium(epsilon=12))]
fsrc = 0.15 # frequency of eigenmode or constant-amplitude source
bnum = 1 # band number of eigenmode
kpoint = mp.Vector3(x=1).rotate(mp.Vector3(z=1), rot_angle)
compute_flux = True # compute flux (True) or plot the field profile (False)
eig_src = True # eigenmode (True) or constant-amplitude (False) source
if eig_src:
sources = [mp.EigenModeSource(src=mp.GaussianSource(fsrc,fwidth=0.2*fsrc) if compute_flux else mp.ContinuousSource(fsrc),
center=mp.Vector3(),
size=mp.Vector3(y=3*w),
direction=mp.NO_DIRECTION,
eig_kpoint=kpoint,
eig_band=bnum,
eig_parity=mp.EVEN_Y+mp.ODD_Z if rot_angle == 0 else mp.ODD_Z,
eig_match_freq=True)]
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:
sim.run(until=100)
sim.plot2D(output_plane=mp.Volume(center=mp.Vector3(), size=mp.Vector3(10,10)),
fields=mp.Ez,
field_parameters={'alpha':0.9})
plt.show()
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