1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
import math
import matplotlib.pyplot as plt
import numpy as np
import meep as mp
def metal_cavity(w):
resolution = 50
sxy = 2
dpml = 1
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(f"ldos:, {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()
|
