tidy3d.GaussianOverlapMonitor

class GaussianOverlapMonitor

Bases: AbstractGaussianOverlapMonitor

Monitor that records amplitudes from decomposition onto a Gaussian beam.

Parameters:

• center (Optional[tuple[Union[float, autograd.tracer.Box], Union[float, autograd.tracer.Box], Union[float, autograd.tracer.Box]]] = None) – [units = um]. Center of object in x, y, and z.

• size (tuple[Union[NonNegativeFloat, autograd.tracer.Box], Union[NonNegativeFloat, autograd.tracer.Box], Union[NonNegativeFloat, autograd.tracer.Box]]) – [units = um]. Size in x, y, and z directions.

• name (str) – Unique name for monitor.

• interval_space (tuple[Literal[1], Literal[1], Literal[1]] = (1, 1, 1)) – Number of grid step intervals between monitor recordings. If equal to 1, there will be no downsampling. If greater than 1, the step will be applied, but the first and last point of the monitor grid are always included. Not all monitors support values different from 1.

• colocate (bool = True) – Toggle whether fields should be colocated to grid cell boundaries (i.e. primal grid nodes).

• use_colocated_integration (bool = True) – Only takes effect when colocate=False. If True, dot products and overlap integrals still use fields interpolated to grid cell boundaries (colocated), even though the field data is stored at native Yee grid positions. Experimental feature that can give improved accuracy by avoiding interpolation of fields to Yee cell positions for integration.

• freqs (ArrayLike[dtype=float, ndim=1]) – [units = Hz]. Array or list of frequencies stored by the field monitor.

• apodization (ApodizationSpec = ApodizationSpec()) – Sets parameters of (optional) apodization. Apodization applies a windowing function to the Fourier transform of the time-domain fields into frequency-domain ones, and can be used to truncate the beginning and/or end of the time signal, for example to eliminate the source pulse when studying the eigenmodes of a system. Note: apodization affects the normalization of the frequency-domain fields.

• store_fields_direction (Optional[Literal['+', '-']] = None) – Propagation direction for the field profiles stored from overlap calculation.

• conjugated_dot_product (bool = True) – Use conjugated or non-conjugated dot product for overlap/decomposition.

• angle_theta (float = 0.0) – [units = rad]. Polar angle of propagation direction.

• angle_phi (float = 0.0) – [units = rad]. Azimuth angle of propagation direction.

• pol_angle (float = 0) – [units = rad]. Specifies the angle between the electric field polarization of the source and the plane defined by the injection axis and the propagation axis (rad). pol_angle=0 (default) specifies P polarization, while pol_angle=np.pi/2 specifies S polarization. At normal incidence when S and P are undefined, pol_angle=0 defines: - Ey polarization for propagation along x.- Ex polarization for propagation along y.- Ex polarization for propagation along z.

• waist_radius (PositiveFloat = 1.0) – [units = um]. Radius of the beam at the waist.

• waist_distance (float = 0.0) – [units = um]. Distance from the beam waist along the propagation direction. A positive value places the waist behind the monitor plane (toward the negative normal axis). A negative value places the waist in front of the monitor plane. For an angled beam, the distance is measured along the rotated propagation direction.

Example

>>> gauss = GaussianOverlapMonitor(
...     size=(0, 3, 3),
...     freqs=[2e14],
...     pol_angle=np.pi / 2,
...     waist_radius=1.0,
...     name="gaussian_monitor",
... )

Notes

If one wants the focus ‘in front’ of the monitor, a negative value of waist_distance is needed. See also GaussianBeam.

Attributes

waist_radius
waist_distance
angle_theta
angle_phi
pol_angle
store_fields_direction
colocate
use_colocated_integration
conjugated_dot_product
freqs
apodization
interval_space
name
size
center

waist_radius

waist_distance