tidy3d.FieldMonitor

class FieldMonitor

Bases: AbstractFieldMonitor, FreqMonitor

Monitor that records electromagnetic fields in the frequency domain.

Parameters:

• 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.

• name (Attribute: name) –

  Type	ConstrainedStrValue
  Default
  Description	Unique name for monitor.

• interval_space (Attribute: interval_space) –

  Type	Tuple[PositiveInt, PositiveInt, PositiveInt]
  Default	= (1, 1, 1)
  Description	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.

• colocate (Attribute: colocate) –

  Type	bool
  Default	= True
  Description	Toggle whether fields should be colocated to grid cell boundaries (i.e. primal grid nodes).

• freqs (Attribute: freqs) –

  Type	Union[Tuple[float, …], ArrayLike[dtype=float, ndim=1]]
  Default
  Units	Hz
  Description	Array or list of frequencies stored by the field monitor.

• apodization (Attribute: apodization) –

  Type	ApodizationSpec
  Default	= ApodizationSpec(startNone, endNone, widthNone, type’ApodizationSpec’)
  Description	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.

• fields (Attribute: fields) –

  Type	Tuple[Literal[‘Ex’, ‘Ey’, ‘Ez’, ‘Hx’, ‘Hy’, ‘Hz’], …]
  Default	= [‘Ex’, ‘Ey’, ‘Ez’, ‘Hx’, ‘Hy’, ‘Hz’]
  Description	Collection of field components to store in the monitor.

Notes

FieldMonitor objects operate by running a discrete Fourier transform of the fields at a given set of frequencies to perform the calculation “in-place” with the time stepping. FieldMonitor objects are useful for investigating the steady-state field distribution in 2D and 3D regions of the simulation.

Example

>>> monitor = FieldMonitor(
...     center=(1,2,3),
...     size=(2,2,2),
...     fields=['Hx'],
...     freqs=[250e12, 300e12],
...     name='steady_state_monitor',
...     colocate=True)

See also

Notebooks

• Quickstart: Usage in a basic simulation flow.

Lectures

• Introduction to FDTD Simulation: Usage in a basic simulation flow.

Attributes

Methods

storage_size(num_cells, tmesh)

Size of monitor storage given the number of points after discretization.

storage_size(num_cells, tmesh)

Size of monitor storage given the number of points after discretization.

__hash__()

Hash method.