class PerturbationMedium[source]#

Bases: Medium, AbstractPerturbationMedium

Dispersionless medium with perturbations.

  • subpixel (bool = True) – This value will be transferred to the resulting custom medium. That is, if True, the subpixel averaging will be applied to the custom medium provided the corresponding Simulation’s field subpixel is set to True as well. If the resulting medium is not a custom medium (no perturbations), this field does not have an effect.

  • name (Optional[str] = None) – Optional unique name for medium.

  • frequency_range (Optional[Tuple[float, float]] = None) – [units = (Hz, Hz)]. Optional range of validity for the medium.

  • allow_gain (bool = False) – Allow the medium to be active. Caution: simulations with a gain medium are unstable, and are likely to diverge.Simulations where ‘allow_gain’ is set to ‘True’ will still be charged even if diverged. Monitor data up to the divergence point will still be returned and can be useful in some cases.

  • nonlinear_spec (Union[NonlinearSpec, NonlinearSusceptibility] = None) – Nonlinear spec applied on top of the base medium properties.

  • modulation_spec (Optional[ModulationSpec] = None) – Modulation spec applied on top of the base medium properties.

  • heat_spec (Union[FluidSpec, SolidSpec, NoneType] = None) – Specification of the medium heat properties. They are used for solving the heat equation via the HeatSimulation interface. Such simulations can be used for investigating the influence of heat propagation on the properties of optical systems. Once the temperature distribution in the system is found using HeatSimulation object, Simulation.perturbed_mediums_copy() can be used to convert mediums with perturbation models defined into spatially dependent custom mediums. Otherwise, the heat_spec does not directly affect the running of an optical Simulation.

  • permittivity (ConstrainedFloatValue = 1.0) – [units = None (relative permittivity)]. Relative permittivity.

  • conductivity (float = 0.0) – [units = S/um]. Electric conductivity. Defined such that the imaginary part of the complex permittivity at angular frequency omega is given by conductivity/omega.

  • permittivity_perturbation (Optional[ParameterPerturbation] = None) – [units = None (relative permittivity)]. List of heat and/or charge perturbations to permittivity.

  • conductivity_perturbation (Optional[ParameterPerturbation] = None) – [units = S/um]. List of heat and/or charge perturbations to permittivity.


>>> from tidy3d import ParameterPerturbation, LinearHeatPerturbation
>>> dielectric = PerturbationMedium(
...     permittivity=4.0,
...     permittivity_perturbation=ParameterPerturbation(
...         heat=LinearHeatPerturbation(temperature_ref=300, coeff=0.0001),
...     ),
...     name='my_medium',
... )



perturbed_copy([temperature, ...])

Sample perturbations on provided heat and/or charge data and return 'CustomMedium'.

Inherited Common Usage

perturbed_copy(temperature=None, electron_density=None, hole_density=None, interp_method='linear')[source]#

Sample perturbations on provided heat and/or charge data and return ‘CustomMedium’. Any of temperature, electron_density, and hole_density can be ‘None’. If all passed arguments are ‘None’ then a ‘Medium’ object is returned. All provided fields must have identical coords.

  • temperature (SpatialDataArray = None) – Temperature field data.

  • electron_density (SpatialDataArray = None) – Electron density field data.

  • hole_density (SpatialDataArray = None) – Hole density field data.

  • interp_method (InterpMethod, optional) – Interpolation method to obtain heat and/or charge values that are not supplied at the Yee grids.


Medium specification after application of heat and/or charge data.

Return type:

Union[Medium, CustomMedium]


Hash method.