tidy3d.DiffractionMonitor

class DiffractionMonitor

Bases: PlanarMonitor, FreqMonitor

Monitor that uses a 2D Fourier transform to compute the diffraction amplitudes and efficiency for allowed diffraction orders.

Parameters:

• center (Tuple[float, float, float] = (0.0, 0.0, 0.0)) – [units = um]. Center of object in x, y, and z.

• size (Tuple[NonNegativeFloat, NonNegativeFloat, NonNegativeFloat]) – [units = um]. Size in x, y, and z directions.

• name (ConstrainedStrValue) – 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 (Literal[False] = False) – Defines whether fields are colocated to grid cell boundaries (i.e. to the primal grid) on-the-fly during a solver run. Can be toggled for field recording monitors and is hard-coded for other monitors depending on their specific function.

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

• apodization (ApodizationSpec = ApodizationSpec(start=None, end=None, width=None, type='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.

• normal_dir (Literal['+', '-'] = +) – Direction of the surface monitor’s normal vector w.r.t. the positive x, y or z unit vectors. Must be one of '+' or '-'. Defaults to '+' if not provided.

Example

>>> monitor = DiffractionMonitor(
...     center=(1,2,3),
...     size=(inf,inf,0),
...     freqs=[250e12, 300e12],
...     name='diffraction_monitor',
...     normal_dir='+',
...     )

See also

Notebooks

• Multilevel blazed diffraction grating

Attributes

Methods

diffraction_monitor_size(val)	Ensure that the monitor is infinite in the transverse direction.
storage_size(num_cells, tmesh)	Size of monitor storage given the number of points after discretization.

normal_dir

colocate

classmethod diffraction_monitor_size(val)

Ensure that the monitor is infinite in the transverse direction.

storage_size(num_cells, tmesh)

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

__hash__()

Hash method.