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from __future__ import division
import math
import meep as mp
import numpy as np
import matplotlib.pyplot as plt
def metal_cavity(w):
resolution = 50
sxy = 2
dpml = 1
sxy = sxy+2*dpml
cell = mp.Vector3(sxy,sxy)
pml_layers = [mp.PML(dpml)]
a = 1
t = 0.1
geometry = [mp.Block(mp.Vector3(a+2*t,a+2*t,mp.inf), material=mp.metal),
mp.Block(mp.Vector3(a,a,mp.inf), material=mp.air)]
geometry.append(mp.Block(center=mp.Vector3(a/2),
size=mp.Vector3(2*t,w,mp.inf),
material=mp.air))
fcen = math.sqrt(0.5)/a
df = 0.2
sources = [mp.Source(src=mp.GaussianSource(fcen,fwidth=df),
component=mp.Ez,
center=mp.Vector3())]
symmetries = [mp.Mirror(mp.Y)]
sim = mp.Simulation(cell_size=cell,
geometry=geometry,
boundary_layers=pml_layers,
sources=sources,
symmetries=symmetries,
resolution=resolution)
h = mp.Harminv(mp.Ez, mp.Vector3(), fcen, df)
sim.run(mp.after_sources(h), until_after_sources=500)
m = h.modes[0]
f = m.freq
Q = m.Q
Vmode = 0.25*a*a
ldos_1 = Q / Vmode / (2 * math.pi * f * math.pi * 0.5)
sim.reset_meep()
T = 2*Q*(1/f)
sim.run(mp.dft_ldos(f,0,1), until_after_sources=T)
ldos_2 = sim.ldos_data[0]
return ldos_1, ldos_2
ws = np.arange(0.2,0.5,0.1)
ldos_1 = np.zeros(len(ws))
ldos_2 = np.zeros(len(ws))
for j in range(len(ws)):
ldos_1[j], ldos_2[j] = metal_cavity(ws[j])
print("ldos:, {}, {}".format(ldos_1[j],ldos_2[2]))
plt.figure(dpi=150)
plt.semilogy(1/ws,ldos_1,'bo-',label="2Q/(πωV)")
plt.semilogy(1/ws,ldos_2,'rs-',label="LDOS")
plt.xlabel('a/w')
plt.ylabel('2Q/(πωW) or LDOS')
plt.show()
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