tidy3d.GaussianBeam#

class GaussianBeam[source]#

Bases: AngledFieldSource, PlanarSource, BroadbandSource

Gaussian distribution on finite extent plane.

Parameters:

attrs (dict = {}) – Dictionary storing arbitrary metadata for a Tidy3D object. This dictionary can be freely used by the user for storing data without affecting the operation of Tidy3D as it is not used internally. Note that, unlike regular Tidy3D fields, attrs are mutable. For example, the following is allowed for setting an attr obj.attrs['foo'] = bar. Also note that Tidy3D` will raise a TypeError if attrs contain objects that can not be serialized. One can check if attrs are serializable by calling obj.json().
name (Optional[str] = None) – Optional name for the source.
center (Union[tuple[Union[float, autograd.tracer.Box], Union[float, autograd.tracer.Box], Union[float, autograd.tracer.Box]], Box] = (0.0, 0.0, 0.0)) – [units = um]. Center of object in x, y, and z.
size (Union[tuple[Union[pydantic.v1.types.NonNegativeFloat, autograd.tracer.Box], Union[pydantic.v1.types.NonNegativeFloat, autograd.tracer.Box], Union[pydantic.v1.types.NonNegativeFloat, autograd.tracer.Box]], Box]) – [units = um]. Size in x, y, and z directions.
source_time (Union[GaussianPulse, ContinuousWave, CustomSourceTime]) – Specification of the source time-dependence.
num_freqs (ConstrainedIntValue = 1) – Number of points used to approximate the frequency dependence of injected field. A Chebyshev interpolation is used, thus, only a small number of points, i.e., less than 20, is typically sufficient to obtain converged results.
direction (Literal['+', '-']) – Specifies propagation in the positive or negative direction of the injection axis.
angle_theta (float = 0.0) – [units = rad]. Polar angle of the propagation axis from the injection axis.
angle_phi (float = 0.0) – [units = rad]. Azimuth angle of the propagation axis in the plane orthogonal to the injection axis.
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 means the waist is positioned behind the source, considering the propagation direction. For example, for a beam propagating in the + direction, a positive value of beam_distance means the beam waist is positioned in the - direction (behind the source). A negative value means the beam waist is in the + direction (in front of the source). For an angled source, the distance is defined along the rotated propagation direction.

Example

>>> pulse = GaussianPulse(freq0=200e12, fwidth=20e12)
>>> gauss = GaussianBeam(
...     size=(0,3,3),
...     source_time=pulse,
...     pol_angle=np.pi / 2,
...     direction='+',
...     waist_radius=1.0)

Notes

If one wants the focus ‘in front’ of the source, a negative value of beam_distance is needed.

tidy3d.GaussianBeam

Contents

tidy3d.GaussianBeam#