How do I model a converging Gaussian beam?

Date	Category
2023-12-11 14:56:49	Sources

To create a converging Gaussian beam, include a tidy3d.GaussianBeam source in the simulation, and set the waist_distance to negative values. This way, the beam waist will lie in the front of the source plane, as illustrated in the following example

# Source bandwidth.
pulse = tidy3d.GaussianPulse(freq0=200e12, fwidth=20e12)

# Source definition
gauss_source = tidy3d.GaussianBeam(
  center=(0, -5, 0),
  size=(0, 3, 3),
  source_time=pulse,
  direction='+',
  pol_angle=0,
  angle_theta=0,
  angle_phi=0,
  waist_radius=1.0,
  waist_distance=-2.5,
  name="gauss_source",
)

See this notebook to an example on setting up a tidy3d.GaussianBeam source.