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## launch a Gaussian beam
import math
import matplotlib
import meep as mp
matplotlib.use("agg")
import matplotlib.pyplot as plt
s = 14
resolution = 50
dpml = 2
cell_size = mp.Vector3(s, s)
boundary_layers = [mp.PML(thickness=dpml)]
beam_x0 = mp.Vector3(0, 3.0) # beam focus (relative to source center)
rot_angle = 0 # CCW rotation angle about z axis (0: +y axis)
beam_kdir = mp.Vector3(0, 1, 0).rotate(
mp.Vector3(0, 0, 1), math.radians(rot_angle)
) # beam propagation direction
beam_w0 = 0.8 # beam waist radius
beam_E0 = mp.Vector3(0, 0, 1)
fcen = 1
sources = [
mp.GaussianBeamSource(
src=mp.ContinuousSource(fcen),
center=mp.Vector3(0, -0.5 * s + dpml + 1.0),
size=mp.Vector3(s),
beam_x0=beam_x0,
beam_kdir=beam_kdir,
beam_w0=beam_w0,
beam_E0=beam_E0,
)
]
sim = mp.Simulation(
resolution=resolution,
cell_size=cell_size,
boundary_layers=boundary_layers,
sources=sources,
)
sim.run(until=20)
sim.plot2D(
fields=mp.Ez,
output_plane=mp.Volume(
center=mp.Vector3(), size=mp.Vector3(s - 2 * dpml, s - 2 * dpml)
),
)
plt.savefig(f"Ez_angle{rot_angle}.png", bbox_inches="tight", pad_inches=0)
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