class Debye[source]#

Bases: DispersiveMedium

A dispersive medium described by the Debye model.

  • 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 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.

  • eps_inf (PositiveFloat = 1.0) – [units = None (relative permittivity)]. Relative permittivity at infinite frequency (\(\epsilon_\infty\)).

  • coeffs (Tuple[Tuple[float, pydantic.v1.types.PositiveFloat], ...]) – [units = (None (relative permittivity), sec)]. List of (\(\Delta\epsilon_i, \tau_i\)) values for model.


The frequency-dependence of the complex-valued permittivity is described by:

\[\epsilon(f) = \epsilon_\infty + \sum_i \frac{\Delta\epsilon_i}{1 - jf\tau_i}\]


>>> debye_medium = Debye(eps_inf=2.0, coeffs=[(1,2),(3,4)])
>>> eps = debye_medium.eps_model(200e12)

See also


A spatially varying dispersive medium described by the Debye model.





Complex-valued permittivity as a function of frequency.

Inherited Common Usage


Complex-valued permittivity as a function of frequency.


Hash method.