tidy3d.LossyMetalMedium

class LossyMetalMedium

Bases: Medium

Lossy metal that can be modeled with a surface impedance boundary condition (SIBC).

Parameters:

• 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 (Tuple[float, float]) – [units = (Hz, Hz)]. Frequency range of validity for the medium.

• allow_gain (Literal[False] = 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.

• viz_spec (Optional[VisualizationSpec] = None) – Plotting specification for visualizing medium.

• heat_spec (Union[FluidSpec, SolidSpec, SolidMedium, FluidMedium, NoneType] = None) – DEPRECATED: Use td.MultiPhysicsMedium. Specification of the medium heat properties. They are used for solving the heat equation via the HeatSimulation interface. Such simulations can beused 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 (Literal[1] = 1.0) – [units = None (relative permittivity)]. Relative permittivity.

• conductivity (Union[float, Box] = 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.

• fit_param (SurfaceImpedanceFitterParam = SurfaceImpedanceFitterParam(attrs={}, max_num_poles=5, tolerance_rms=0.001, frequency_sampling_points=20, log_sampling=True, type='SurfaceImpedanceFitterParam')) – Parameters for fitting surface impedance divided by (-1j * omega) over the frequency range using pole-residue pair model.

Notes

SIBC is most accurate when the skin depth is much smaller than the structure feature size. If not the case, please use a regular medium instead, or set simulation.subpixel.lossy_metal to td.VolumetricAveraging() or td.Staircasing().

Example

>>> lossy_metal = LossyMetalMedium(conductivity=10, frequency_range=(9e9, 10e9))

Attributes

num_poles	Number of poles in the fitted model.
sampling_frequencies	Sampling frequencies used in fitting.
scaled_surface_impedance_model	Fitted surface impedance divided by (-j omega) using pole-residue pair model within frequency_range.
attrs

Methods

eps_diagonal_numerical(frequency)	Main diagonal of the complex-valued permittivity tensor for numerical considerations such as meshing and runtime estimation.
plot([ax])	Make plot of complex-valued surface imepdance model vs fitted model, at sampling frequencies.
surface_impedance(frequencies)	Computing surface impedance.

Inherited Common Usage

allow_gain

permittivity

frequency_range

fit_param

property scaled_surface_impedance_model

Fitted surface impedance divided by (-j omega) using pole-residue pair model within frequency_range.

property num_poles

Number of poles in the fitted model.

surface_impedance(frequencies)

Computing surface impedance.

property sampling_frequencies

Sampling frequencies used in fitting.

eps_diagonal_numerical(frequency)

Main diagonal of the complex-valued permittivity tensor for numerical considerations such as meshing and runtime estimation.

Parameters:

frequency (float) – Frequency to evaluate permittivity at (Hz).

Returns:

The diagonal elements of relative permittivity tensor relevant for numerical considerations evaluated at frequency.

Return type:

Tuple[complex, complex, complex]

plot(ax=None)

Make plot of complex-valued surface imepdance model vs fitted model, at sampling frequencies. :param ax: Axes to plot the data on, if None, a new one is created. :type ax: matplotlib.axes._subplots.Axes = None

Returns:

Matplotlib axis corresponding to plot.

Return type:

matplotlib.axis.Axes

__hash__()

Hash method.