tidy3d.AstigmaticGaussianBeam

class AstigmaticGaussianBeam

Bases: AngledFieldSource, PlanarSource, BroadbandSource

The simple astigmatic Gaussian distribution allows both an elliptical intensity profile and different waist locations for the two principal axes of the ellipse. When equal waist sizes and equal waist distances are specified in the two directions, this source becomes equivalent to GaussianBeam.

Parameters:

• name (Attribute: name) –

  Type	Optional[str]
  Default	= None
  Description	Optional name for the source.

• center (Attribute: center) –

  Type	Tuple[float, float, float]
  Default	= (0.0, 0.0, 0.0)
  Units	um
  Description	Center of object in x, y, and z.

• size (Attribute: size) –

  Type	Tuple[NonNegativeFloat, NonNegativeFloat, NonNegativeFloat]
  Default
  Units	um
  Description	Size in x, y, and z directions.

• source_time (Attribute: source_time) –

  Type	Union[GaussianPulse, ContinuousWave, CustomSourceTime]
  Default
  Description	Specification of the source time-dependence.

• num_freqs (Attribute: num_freqs) –

  Type	ConstrainedIntValue
  Default	= 1
  Description	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 (Attribute: direction) –

  Type	Literal[‘+’, ‘-‘]
  Default
  Description	Specifies propagation in the positive or negative direction of the injection axis.

• angle_theta (Attribute: angle_theta) –

  Type	float
  Default	= 0.0
  Units	rad
  Description	Polar angle of the propagation axis from the injection axis.

• angle_phi (Attribute: angle_phi) –

  Type	float
  Default	= 0.0
  Units	rad
  Description	Azimuth angle of the propagation axis in the plane orthogonal to the injection axis.

• pol_angle (Attribute: pol_angle) –

  Type	float
  Default	= 0
  Units	rad
  Description	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_sizes (Attribute: waist_sizes) –

  Type	Tuple[PositiveFloat, PositiveFloat]
  Default	= (1.0, 1.0)
  Units	um
  Description	Size of the beam at the waist in the local x and y directions.

• waist_distances (Attribute: waist_distances) –

  Type	Tuple[float, float]
  Default	= (0.0, 0.0)
  Units	um
  Description	Distance to the beam waist along the propagation direction for the waist sizes in the local x and y directions. When direction is + and waist_distances are positive, the waist is on the - side (behind) the source plane. When direction is + and waist_distances are negative, the waist is on the + side (in front) of the source plane.

Notes

This class implements the simple astigmatic Gaussian beam described in [1].

References:

[1]

Kochkina et al., Applied Optics, vol. 52, issue 24, 2013.

Example

>>> pulse = GaussianPulse(freq0=200e12, fwidth=20e12)
>>> gauss = AstigmaticGaussianBeam(
...     size=(0,3,3),
...     source_time=pulse,
...     pol_angle=np.pi / 2,
...     direction='+',
...     waist_sizes=(1.0, 2.0),
...     waist_distances = (3.0, 4.0))

Attributes

Methods

waist_sizes

waist_distances

__hash__()

Hash method.