tidy3d.plugins.adjoint.JaxCustomMedium

class JaxCustomMedium

Bases: CustomMedium, AbstractJaxMedium

A CustomMedium registered with jax. Note: The gradient calculation assumes uniform field across the pixel. Therefore, the accuracy degrades as the pixel size becomes large with respect to the field variation.

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 (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.

• interp_method (Literal['nearest', 'linear'] = nearest) – Interpolation method to obtain permittivity values that are not supplied at the Yee grids; For grids outside the range of the supplied data, extrapolation will be applied. When the extrapolated value is smaller (greater) than the minimal (maximal) of the supplied data, the extrapolated value will take the minimal (maximal) of the supplied data.

• subpixel (bool = False) – If True, apply the subpixel averaging method specified by Simulation’s field subpixel for this type of material on the interface of the structure, including exterior boundary and intersection interfaces with other structures.

• eps_dataset (Optional[JaxPermittivityDataset] = None) – User-supplied dataset containing complex-valued permittivity as a function of space. Permittivity distribution over the Yee-grid will be interpolated based on the data nearest to the grid location.

• permittivity (Union[SpatialDataArray, Annotated[Union[tidy3d.components.data.dataset.TriangularGridDataset, tidy3d.components.data.dataset.TetrahedralGridDataset], FieldInfo(default=PydanticUndefined, discriminator='type', extra={})], NoneType] = None) – [units = None (relative permittivity)]. Spatial profile of relative permittivity.

• conductivity (Union[SpatialDataArray, Annotated[Union[tidy3d.components.data.dataset.TriangularGridDataset, tidy3d.components.data.dataset.TetrahedralGridDataset], FieldInfo(default=PydanticUndefined, discriminator='type', extra={})], NoneType] = None) – [units = S/um]. Spatial profile Electric conductivity. Defined such that the imaginary part of the complex permittivity at angular frequency omega is given by conductivity/omega.

Attributes

attrs

Methods

store_vjp(grad_data_fwd, grad_data_adj, ...)

Returns the gradient of the medium parameters given forward and adjoint field data.

Inherited Common Usage

eps_dataset

store_vjp(grad_data_fwd, grad_data_adj, sim_bounds, wvl_mat, inside_fn)

Returns the gradient of the medium parameters given forward and adjoint field data.

__hash__()

Hash method.