mirror of
https://github.com/edoverg/modeconverter.git
synced 2026-10-14 23:06:39 +00:00
added full_meta_meep and meep_fullmeta_propagation which contain first attempts at using meep for computing the whole system. At first, we check propagation using meep_fullmeta_propagation and will later introduce pillars after verification.
This commit is contained in:
Edoardo Vergerio
@@ -0,0 +1,282 @@
|
||||
import meep as mp
|
||||
mp.verbosity(1)
|
||||
|
||||
import numpy as np
|
||||
import matplotlib.pyplot as plt
|
||||
|
||||
resolution = 15 #[px/um]
|
||||
|
||||
#all dimensions in [um]
|
||||
lda0 = 1.55
|
||||
freq0 = 1 / lda0
|
||||
wvl_min = 1.5
|
||||
wvl_max = 1.6
|
||||
wvl_cen = lda0
|
||||
fmin = 1/wvl_max
|
||||
fmax = 1/wvl_min
|
||||
fcen = 1/wvl_cen
|
||||
df = fmax-fmin
|
||||
fwidth = df
|
||||
nfreq = 1
|
||||
|
||||
dpml = 0.5 #PML thickness
|
||||
dsub = 0.2*lda0 #substrate thickness
|
||||
#dpad = dsub #padding between cell and PML
|
||||
|
||||
n_si = 3.45 #silicon refractive index
|
||||
si = mp.Medium(index = n_si)
|
||||
n_sio2 = 1.45
|
||||
sio2 = mp.Medium(index = n_sio2)
|
||||
n_air = 1.0 #air refractive index
|
||||
air = mp.Medium(index = n_air)
|
||||
|
||||
P = 0.7 #unit cell pitch [um]
|
||||
unit_cell_pitch = P
|
||||
h = 0.9 #pillar height [um]
|
||||
|
||||
#propgation distances
|
||||
d0 = 535 #[um]
|
||||
d1 = 415 #[um]
|
||||
d2 = d0 #[um]
|
||||
|
||||
Nx = 1025 #pixels per dimension
|
||||
Ny = Nx
|
||||
nx = (Nx - 1) // 2 #indices without axes (= #512)
|
||||
ny = (Ny - 1) // 2
|
||||
dof = 2*((nx + 1)**2) #number of degrees of freedom per metasurface
|
||||
S = Nx * Ny
|
||||
|
||||
size_x = unit_cell_pitch * Nx #actual physical size
|
||||
size_y = unit_cell_pitch * Ny
|
||||
|
||||
xs = np.arange(-Nx//2+1, Nx//2+1) * (size_x / Nx)
|
||||
ys = np.arange(-Ny//2+1, Ny//2+1) * (size_y / Ny)
|
||||
print(xs[0],xs[-1])
|
||||
X, Y = np.meshgrid(xs, ys)
|
||||
rho = np.sqrt(X**2 + Y**2)
|
||||
|
||||
|
||||
####################################################
|
||||
#LOAD PHASE MASK
|
||||
#___________________________________________________
|
||||
#load the phase mask data
|
||||
phase_mask_filename = "../results_sym/optimized_phase_mask_1.npy"
|
||||
phase_mask = np.load(phase_mask_filename)
|
||||
|
||||
fig, ax = plt.subplots()
|
||||
im = ax.pcolormesh(X, Y, phase_mask, cmap='hsv', shading='auto')
|
||||
ax.set_xlabel('X [um]')
|
||||
ax.set_ylabel('Y [um]')
|
||||
fig.show()
|
||||
|
||||
#sim_domain_pixel_size = #full simulation domain (full axis)
|
||||
sim_domain_size = 140 #[um]
|
||||
|
||||
max_sim_radius = 60
|
||||
|
||||
X_quadrant = X[nx:, ny:]
|
||||
xs_quadrant = xs[nx:]
|
||||
xs_sim = xs[np.abs(xs) <= sim_domain_size/2]
|
||||
xs_sim_quadrant = xs_quadrant[np.abs(xs_quadrant) <= sim_domain_size/2]
|
||||
|
||||
Y_quadrant = Y[nx:, ny:]
|
||||
ys_quadrant = ys[ny:]
|
||||
ys_sim = ys[np.abs(ys) <= sim_domain_size/2]
|
||||
ys_sim_quadrant = ys_quadrant[np.abs(ys_quadrant) <= sim_domain_size/2]
|
||||
|
||||
X_sim, Y_sim = np.meshgrid(xs_sim, ys_sim)
|
||||
|
||||
phase_mask_quadrant = phase_mask[nx:, ny:]
|
||||
|
||||
fig, ax = plt.subplots()
|
||||
im = ax.pcolormesh(X_quadrant, Y_quadrant, phase_mask_quadrant, cmap='hsv', shading='auto')
|
||||
ax.set_xlabel('X [um]')
|
||||
ax.set_ylabel('Y [um]')
|
||||
ax.set_ybound(0,sim_domain_size/2)
|
||||
ax.set_xbound(0,sim_domain_size/2)
|
||||
fig.show()
|
||||
|
||||
|
||||
|
||||
####################################################
|
||||
#UNIT CELL DATA
|
||||
#___________________________________________________
|
||||
#import the unit-cell transmission coefficient data
|
||||
unit_cell_diameters = np.load("../unit_cell/unit_cell_center_1550_h900nm_res50_wvl_diameters.npy")
|
||||
unit_cell_mode_phase = np.load("../unit_cell/unit_cell_center_1550_h900nm_res50_wvl_mode_phase.npy")
|
||||
unit_cell_mode_phase = np.unwrap(unit_cell_mode_phase - unit_cell_mode_phase[0]) #normalize to 0 phase at smallest diameter
|
||||
unit_cell_mode_tran = np.load("../unit_cell/unit_cell_center_1550_h900nm_res50_wvl_mode_tran.npy")
|
||||
|
||||
#make a plot of the unit-cell transmission coefficient
|
||||
fig, ax = plt.subplots(1, 2, figsize=(10, 4))
|
||||
ax[0].plot(unit_cell_diameters, unit_cell_mode_phase, 'r-', marker='o', label='Phase')
|
||||
ax[0].set_xlabel('Diameter (um)')
|
||||
ax[0].set_ylabel('Phase (rad)')
|
||||
ax[1].plot(unit_cell_diameters, unit_cell_mode_tran, 'b-', marker='o', label='Transmission')
|
||||
ax[1].set_xlabel('Diameter (um)')
|
||||
ax[1].set_ylabel('Amplitude')
|
||||
ax[0].legend()
|
||||
ax[1].legend()
|
||||
plt.show()
|
||||
####################################################
|
||||
|
||||
pillars_geo = []
|
||||
D_vals = []
|
||||
theta = unit_cell_mode_phase
|
||||
|
||||
for i, x in enumerate(xs_sim_quadrant):
|
||||
for j, y in enumerate(ys_sim_quadrant):
|
||||
if np.sqrt(x**2 + y**2) > max_sim_radius:
|
||||
continue
|
||||
else:
|
||||
required_diameter = np.interp(phase_mask_quadrant[i,j], theta, unit_cell_diameters)
|
||||
#round the required diameter up to three decimal places (nm)
|
||||
required_diameter = np.round(required_diameter, 3)
|
||||
D_vals.append(required_diameter)
|
||||
pillar_geo = mp.Cylinder(
|
||||
material=si,
|
||||
radius=required_diameter/2,
|
||||
height=h,
|
||||
center=mp.Vector3(x, y, h/2),
|
||||
axis=mp.Vector3(0, 0, 1),
|
||||
)
|
||||
pillars_geo.append(pillar_geo)
|
||||
print("Number of pillars in simulation domain: ", len(pillars_geo))
|
||||
|
||||
#import the input field (just before MS1)
|
||||
input_field = np.load("../results_sym/input_field.npy")
|
||||
|
||||
mask = (np.abs(X) <= sim_domain_size/2) & (np.abs(Y) <= sim_domain_size/2)
|
||||
|
||||
eta_0 = 1 #due to meep's internal normalization
|
||||
Ex_field_after_MS1 = input_field * np.exp(1j*phase_mask) / np.max(np.abs(input_field))
|
||||
|
||||
Ex_field_after_MS1_sim = Ex_field_after_MS1[mask].reshape((len(xs_sim), len(ys_sim)))
|
||||
Hy_field_after_MS1_sim = Ex_field_after_MS1_sim / eta_0
|
||||
|
||||
fig, ax = plt.subplots()
|
||||
im = ax.pcolormesh(X_sim, Y_sim, np.abs(Ex_field_after_MS1_sim))
|
||||
ax.set_xlabel('X [um]')
|
||||
ax.set_ylabel('Y [um]')
|
||||
|
||||
fig.colorbar(im, ax=ax)
|
||||
|
||||
fig,ax = plt.subplots()
|
||||
im = ax.pcolormesh(X_sim, Y_sim, (np.angle(Ex_field_after_MS1_sim)+2*np.pi)%(2*np.pi), cmap='hsv', shading='auto')
|
||||
ax.set_xlabel('X [um]')
|
||||
ax.set_ylabel('Y [um]')
|
||||
|
||||
fig.colorbar(im, ax=ax)
|
||||
|
||||
# [markdown]
|
||||
# for the equivalence principle, if we want to use the field after MS1
|
||||
# as an actual source, we need to define proper magnetic and electric currents
|
||||
# we assume the input electric field is polarized along the x-axis
|
||||
# and the magnetic field is polarized along the y-axis.
|
||||
# Specifying both electric and magnetic fields is necessary
|
||||
# to obtain a directional source.
|
||||
|
||||
#define the source field dataset
|
||||
source_position = mp.Vector3(0,0,-0.1)
|
||||
|
||||
#the surface currents due to the equivalance principle are:
|
||||
#Js_x = -Hy_field_after_MS1
|
||||
#Ms_y = -Ex_field_after_MS1
|
||||
|
||||
sources = [
|
||||
mp.Source(#electric current
|
||||
src=mp.GaussianSource(frequency=freq0, fwidth=fwidth),
|
||||
component=mp.Ex,
|
||||
center=source_position,
|
||||
size=mp.Vector3(sim_domain_size, sim_domain_size, 0),
|
||||
amplitude=-1,
|
||||
amp_data=Hy_field_after_MS1_sim[:, :, np.newaxis]
|
||||
),
|
||||
|
||||
mp.Source(#magnetic current
|
||||
src=mp.GaussianSource(frequency=freq0, fwidth=fwidth),
|
||||
component=mp.Hy,
|
||||
center=source_position,
|
||||
size=mp.Vector3(sim_domain_size, sim_domain_size, 0),
|
||||
amplitude=-1,
|
||||
amp_data=Ex_field_after_MS1_sim[:, :, np.newaxis]
|
||||
),
|
||||
]
|
||||
|
||||
pml_layers = [mp.PML(dpml)]
|
||||
|
||||
Lx = sim_domain_size + 2*dpml
|
||||
Ly = sim_domain_size + 2*dpml
|
||||
Lz = 2*dpml + 0.4
|
||||
|
||||
cell_size = mp.Vector3(Lx, Ly, Lz)
|
||||
|
||||
sim = mp.Simulation(
|
||||
resolution=resolution,
|
||||
cell_size = cell_size,
|
||||
boundary_layers = pml_layers,
|
||||
default_material = air,
|
||||
sources = sources,
|
||||
symmetries = [mp.Mirror(0, phase=-1), mp.Mirror(1, phase=+1)]
|
||||
)
|
||||
|
||||
|
||||
#far field points for projection monitor
|
||||
ff_resolution = 5
|
||||
ff_plane_size = 30 #[um]
|
||||
|
||||
xs_far = np.linspace(-ff_plane_size/2, ff_plane_size/2, ff_resolution * ff_plane_size)
|
||||
ys_far = np.linspace(-ff_plane_size/2, ff_plane_size/2, ff_resolution * ff_plane_size)
|
||||
|
||||
X_far, Y_far = np.meshgrid(xs_far, ys_far)
|
||||
|
||||
projection_distance = h + d1 - lda0 / 2
|
||||
|
||||
near_region_monitor = mp.Near2FarRegion(
|
||||
center=mp.Vector3(0, 0, 0),
|
||||
size=mp.Vector3(sim_domain_size, sim_domain_size, 0),
|
||||
)
|
||||
|
||||
n2f_obj = sim.add_near2far([freq0], near_region_monitor)
|
||||
|
||||
#flux_mon = sim.add_flux(
|
||||
# [fcen],
|
||||
# mp.FluxRegion(center=mp.Vector3(0,0,0), size=mp.Vector3(sim_domain_size, sim_domain_size, 0))
|
||||
# )
|
||||
|
||||
fig, ax = plt.subplots()
|
||||
plot_xz_plane = mp.Volume(center=mp.Vector3(0,0,0), size=mp.Vector3(Lx, 0, Lz))
|
||||
sim.plot2D(ax=ax,output_plane=plot_xz_plane)
|
||||
ax.set_aspect('auto')
|
||||
|
||||
obs_point = mp.Vector3(0,0,0)
|
||||
stop_cond = mp.stop_when_fields_decayed(50, mp.Ez, obs_point, 1e-9)
|
||||
|
||||
sim.run(until_after_sources=stop_cond)
|
||||
|
||||
|
||||
far_plane = mp.Volume(
|
||||
center=mp.Vector3(0, 0, projection_distance),
|
||||
size=mp.Vector3(ff_plane_size, ff_plane_size, 0)
|
||||
)
|
||||
|
||||
ff_data = sim.get_farfields(n2f_obj, ff_resolution, where=far_plane)
|
||||
|
||||
ff_Ex = ff_data['Ex']
|
||||
np.save("ff_Ex.npy", ff_Ex)
|
||||
|
||||
fig, ax = plt.subplots()
|
||||
im = ax.pcolormesh(X_far, Y_far, np.abs(ff_Ex), cmap='viridis', shading='auto')
|
||||
ax.set_xlabel('X [um]')
|
||||
ax.set_ylabel('Y [um]')
|
||||
fig.colorbar(im, ax=ax)
|
||||
fig.savefig("magnitude_field_before_MS2.pdf")
|
||||
|
||||
#make a line plot that is a slice along the y=0 axis
|
||||
fig, az = plt.subplots()
|
||||
im = az.plot(xs_far, np.abs(ff_Ex[ff_resolution * ff_plane_size//2, :]))
|
||||
az.set_xlabel('X [um]')
|
||||
az.set_ylabel('Magnitude of E-field')
|
||||
fig.savefig("magnitude_field_before_MS2_slice.pdf")
|
||||
|
||||
|
||||
Reference in New Issue
Block a user