How do I set the Absorber boundary condition?

Date	Category
2023-12-15 20:59:51	Boundary Conditions

The tidy3d.Absorber boundary condition specifies an adiabatic absorber along a single dimension. This absorber is well-suited for dispersive materials intersecting with absorbing edges of the simulation at the expense of more layers. The example below shows how to set up an absorbing boundary.

# Define PML boundary conditions in all sides.
bspec = tidy3d.BoundarySpec.all_sides(boundary=tidy3d.Absorber(num_layers=40))

# Build the simulation.
sim = tidy3d.Simulation(
    center=(0, 0, 0),
    size=(10, 4, 4),
    boundary_spec=bspec,
    grid_spec=tidy3d.GridSpec.auto(min_steps_per_wvl=20, wavelength=1.55),
    structures=[waveguide],
    sources=[mode_source],
    monitors=[mode_monitor],
    run_time=1e-12,
)

See this notebook for more details on setting up boundary conditions.