def test_faraday_rotation(self):
L, zsrc, zout = 12.0, -4.5, 4.0
freq, tmax = 0.8, 100.0
resolution = 24
## Test gyrotropic Lorentzian medium
epsn, f0, gamma, sn, b0 = 1.5, 1.0, 1e-3, 0.1, 0.15
susc = [mp.GyrotropicLorentzianSusceptibility(frequency=f0, gamma=gamma, sigma=sn,
bias=mp.Vector3(0, 0, b0))]
mat = mp.Medium(epsilon=epsn, mu=1, E_susceptibilities=susc)
k = kgyro_lorentzian(freq, epsn, f0, gamma, sn, b0)
print('=' * 24)
print("Testing Faraday rotation for gyrotropic Lorentzian model...")
self.check_rotation(mat, L, freq, zsrc, resolution, tmax, zout, k)
## Test gyrotropic Drude medium
susc = [mp.GyrotropicDrudeSusceptibility(frequency=f0, gamma=gamma, sigma=sn,
bias=mp.Vector3(0, 0, b0))]
mat = mp.Medium(epsilon=epsn, mu=1, E_susceptibilities=susc)
k = kgyro_drude(freq, epsn, f0, gamma, sn, b0)
print('=' * 24)
print("Testing Faraday rotation for gyrotropic Drude model...")
self.check_rotation(mat, L, freq, zsrc, resolution, tmax, zout, k)
## Test Landau-Lifshitz-Gilbert medium
alpha = 1e-5
susc = [mp.GyrotropicSaturatedSusceptibility(frequency=f0, gamma=gamma, sigma=sn,
alpha=alpha,
bias=mp.Vector3(0, 0, 1.0))]
mat = mp.Medium(epsilon=epsn, mu=1, E_susceptibilities=susc)
k = kgyro_llg(freq, epsn, f0, gamma, sn, alpha)
print('=' * 24)
print("Testing Faraday rotation for Landau-Lifshitz-Gilbert model...")
self.check_rotation(mat, L, freq, zsrc, resolution, tmax, zout, k)
def gyrotropic_conversion(material, bias):
if bias.norm() != 0:
material_suc = []
for susceptibility in material.E_susceptibilities:
if type(susceptibility).__name__ == 'DrudeSusceptibility':
material_suc.append(
mp.GyrotropicDrudeSusceptibility(frequency=susceptibility.frequency, gamma=susceptibility.gamma,
sigma=susceptibility.sigma_diag.x, bias=bias))
elif type(susceptibility).__name__ == 'LorentzianSusceptibility':
material_suc.append(
mp.GyrotropicLorentzianSusceptibility(frequency=susceptibility.frequency,
gamma=susceptibility.gamma,
sigma=susceptibility.sigma_diag.x, bias=bias))
return mp.Medium(epsilon=material.epsilon_diag.x, E_susceptibilities=material_suc,
valid_freq_range=material.valid_freq_range)
return material
# From the Meep tutorial: plotting Faraday rotation of a linearly polarized plane wave
import meep as mp
# Parameters for a gyrotropic Lorentzian medium
epsn = 1.5 # background permittivity
f0 = 1.0 # natural frequency
gamma = 1e-6 # damping rate
sn = 0.1 # sigma parameter
b0 = 0.15 # magnitude of bias vector
susc = [
mp.GyrotropicLorentzianSusceptibility(frequency=f0,
gamma=gamma,
sigma=sn,
bias=mp.Vector3(0, 0, b0))
]
mat = mp.Medium(epsilon=epsn, mu=1, E_susceptibilities=susc)
# Set up and run the Meep simulation:
tmax = 100
L = 20.0
cell = mp.Vector3(0, 0, L)
fsrc, src_z = 0.8, -8.5
pml_layers = [mp.PML(thickness=1.0, direction=mp.Z)]
sources = [
mp.Source(mp.ContinuousSource(frequency=fsrc),
component=mp.Ex,
center=mp.Vector3(0, 0, src_z))
]