tidy3d.components.medium.AbstractMedium#

class tidy3d.components.medium.AbstractMedium#

Bases: abc.ABC, tidy3d.components.base.Tidy3dBaseModel

A medium within which electromagnetic waves propagate.

Parameters

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.

Show JSON schema

{
   "title": "AbstractMedium",
   "description": "A medium within which electromagnetic waves propagate.\n\nParameters\n----------\nname : Optional[str] = None\n    Optional unique name for medium.\nfrequency_range : Optional[Tuple[float, float]] = None\n    [units = (Hz, Hz)].  Optional range of validity for the medium.",
   "type": "object",
   "properties": {
      "name": {
         "title": "Name",
         "description": "Optional unique name for medium.",
         "type": "string"
      },
      "frequency_range": {
         "title": "Frequency Range",
         "description": "Optional range of validity for the medium.",
         "units": [
            "Hz",
            "Hz"
         ],
         "type": "array",
         "minItems": 2,
         "maxItems": 2,
         "items": [
            {
               "type": "number"
            },
            {
               "type": "number"
            }
         ]
      },
      "type": {
         "title": "Type",
         "default": "AbstractMedium",
         "enum": [
            "AbstractMedium"
         ],
         "type": "string"
      }
   },
   "additionalProperties": false
}

attribute frequency_range: Tuple[float, float] = None#: Optional range of validity for the medium.

attribute name: str = None#

Optional unique name for medium.

Validated by

field_has_unique_names

classmethod add_type_field() → None#: Automatically place “type” field with model name in the model field dictionary.

classmethod construct(_fields_set: Optional[SetStr] = None, **values: Any) → Model#: Creates a new model setting __dict__ and __fields_set__ from trusted or pre-validated data. Default values are respected, but no other validation is performed. Behaves as if Config.extra = ‘allow’ was set since it adds all passed values

copy(**kwargs) → tidy3d.components.base.Tidy3dBaseModel#: Copy a Tidy3dBaseModel. With deep=True as default.

dict(*, include: Optional[Union[AbstractSetIntStr, MappingIntStrAny]] = None, exclude: Optional[Union[AbstractSetIntStr, MappingIntStrAny]] = None, by_alias: bool = False, skip_defaults: Optional[bool] = None, exclude_unset: bool = False, exclude_defaults: bool = False, exclude_none: bool = False) → DictStrAny#: Generate a dictionary representation of the model, optionally specifying which fields to include or exclude.

classmethod dict_from_file(fname: str, group_path: Optional[str] = None) → dict#

Loads a dictionary containing the model from a .yaml, .json, or .hdf5 file.

Parameters

fname (str) – Full path to the .yaml or .json file to load the Tidy3dBaseModel from.
group_path (str, optional) – Path to a group inside the file to use as the base level.

Returns

A dictionary containing the model.

Return type

dict

Example

>>> simulation = Simulation.from_file(fname='folder/sim.json') 

classmethod dict_from_hdf5(fname: str, group_path: str = '') → dict#

Loads a dictionary containing the model contents from a .hdf5 file.

Parameters

fname (str) – Full path to the .hdf5 file to load the Tidy3dBaseModel from.
group_path (str, optional) – Path to a group inside the file to selectively load a sub-element of the model only.

Returns

Dictionary containing the model.

Return type

dict

Example

>>> sim_dict = Simulation.dict_from_hdf5(fname='folder/sim.hdf5') 

classmethod dict_from_json(fname: str) → dict#

Load dictionary of the model from a .json file.

Parameters: fname (str) – Full path to the .json file to load the Tidy3dBaseModel from.
Returns: A dictionary containing the model.
Return type: dict

Example

>>> sim_dict = Simulation.dict_from_json(fname='folder/sim.json') 

classmethod dict_from_yaml(fname: str) → dict#

Load dictionary of the model from a .yaml file.

Parameters: fname (str) – Full path to the .yaml file to load the Tidy3dBaseModel from.
Returns: A dictionary containing the model.
Return type: dict

Example

>>> sim_dict = Simulation.dict_from_yaml(fname='folder/sim.yaml') 

static eps_complex_to_eps_sigma(eps_complex: complex, freq: float) → Tuple[float, float]#

Convert complex permittivity at frequency freq to permittivity and conductivity values.

Parameters

eps_complex (complex) – Complex-valued relative permittivity.
freq (float) – Frequency to evaluate permittivity at (Hz).

Returns

Real part of relative permittivity & electric conductivity.

Return type

Tuple[float, float]

static eps_complex_to_nk(eps_c: complex) → Tuple[float, float]#

Convert complex permittivity to n, k values.

Parameters: eps_c (complex) – Complex-valued relative permittivity.
Returns: Real and imaginary parts of refractive index (n & k).
Return type: Tuple[float, float]

eps_diagonal(frequency: float) → Tuple[complex, complex, complex]#

Main diagonal of the complex-valued permittivity tensor as a function of frequency.

Parameters: frequency (float) – Frequency to evaluate permittivity at (Hz).
Returns: The diagonal elements of the relative permittivity tensor evaluated at frequency.
Return type: complex

abstract eps_model(frequency: float) → complex#

Complex-valued permittivity as a function of frequency.

Parameters: frequency (float) – Frequency to evaluate permittivity at (Hz).
Returns: Complex-valued relative permittivity evaluated at frequency.
Return type: complex

static eps_sigma_to_eps_complex(eps_real: float, sigma: float, freq: float) → complex#

convert permittivity and conductivity to complex permittivity at freq

Parameters

eps_real (float) – Real-valued relative permittivity.
sigma (float) – Conductivity.
freq (float) – Frequency to evaluate permittivity at (Hz). If not supplied, returns real part of permittivity (limit as frequency -> infinity.)

Returns

Complex-valued relative permittivity.

Return type

complex

classmethod from_file(fname: str, group_path: Optional[str] = None, **parse_obj_kwargs) → tidy3d.components.base.Tidy3dBaseModel#

Loads a Tidy3dBaseModel from .yaml, .json, or .hdf5 file.

Parameters

fname (str) – Full path to the .yaml or .json file to load the Tidy3dBaseModel from.
group_path (str, optional) – Path to a group inside the file to use as the base level. Only for .hdf5 files. Starting / is optional.
**parse_obj_kwargs – Keyword arguments passed to either pydantic’s parse_obj function when loading model.

Returns

An instance of the component class calling load.

Return type

Tidy3dBaseModel

Example

>>> simulation = Simulation.from_file(fname='folder/sim.json') 

classmethod from_hdf5(fname: str, group_path: str = '', **parse_obj_kwargs) → tidy3d.components.base.Tidy3dBaseModel#

Loads Tidy3dBaseModel instance to .hdf5 file.

Parameters

fname (str) – Full path to the .hdf5 file to load the Tidy3dBaseModel from.
group_path (str, optional) – Path to a group inside the file to selectively load a sub-element of the model only. Starting / is optional.
**parse_obj_kwargs – Keyword arguments passed to pydantic’s parse_obj method.

Example

>>> simulation.to_hdf5(fname='folder/sim.hdf5') 

classmethod from_json(fname: str, **parse_obj_kwargs) → tidy3d.components.base.Tidy3dBaseModel#

Load a Tidy3dBaseModel from .json file.

Parameters

fname (str) – Full path to the .json file to load the Tidy3dBaseModel from.

Returns

Tidy3dBaseModel – An instance of the component class calling load.
**parse_obj_kwargs – Keyword arguments passed to pydantic’s parse_obj method.

Example

>>> simulation = Simulation.from_json(fname='folder/sim.json') 

classmethod from_orm(obj: Any) → Model#

classmethod from_yaml(fname: str, **parse_obj_kwargs) → tidy3d.components.base.Tidy3dBaseModel#

Loads Tidy3dBaseModel from .yaml file.

Parameters

fname (str) – Full path to the .yaml file to load the Tidy3dBaseModel from.
**parse_obj_kwargs – Keyword arguments passed to pydantic’s parse_obj method.

Returns

An instance of the component class calling from_yaml.

Return type

Tidy3dBaseModel

Example

>>> simulation = Simulation.from_yaml(fname='folder/sim.yaml') 

classmethod generate_docstring() → str#: Generates a docstring for a Tidy3D mode and saves it to the __doc__ of the class.

classmethod get_sub_model(group_path: str, model_dict: dict | list) → dict#: Get the sub model for a given group path.

static get_tuple_group_name(index: int) → str#: Get the group name of a tuple element.

static get_tuple_index(key_name: str) → int#: Get the index into the tuple based on its group name.

help(methods: bool = False) → None#

Prints message describing the fields and methods of a Tidy3dBaseModel.

Parameters: methods (bool = False) – Whether to also print out information about object’s methods.

Example

>>> simulation.help(methods=True) 

json(*, include: Optional[Union[AbstractSetIntStr, MappingIntStrAny]] = None, exclude: Optional[Union[AbstractSetIntStr, MappingIntStrAny]] = None, by_alias: bool = False, skip_defaults: Optional[bool] = None, exclude_unset: bool = False, exclude_defaults: bool = False, exclude_none: bool = False, encoder: Optional[Callable[[Any], Any]] = None, models_as_dict: bool = True, **dumps_kwargs: Any) → unicode#

Generate a JSON representation of the model, include and exclude arguments as per dict().

encoder is an optional function to supply as default to json.dumps(), other arguments as per json.dumps().

nk_model(frequency: float) → Tuple[float, float]#

Real and imaginary parts of the refactive index as a function of frequency.

Parameters: frequency (float) – Frequency to evaluate permittivity at (Hz).
Returns: Real part (n) and imaginary part (k) of refractive index of medium.
Return type: Tuple[float, float]

static nk_to_eps_complex(n: float, k: float = 0.0) → complex#

Convert n, k to complex permittivity.

Parameters

n (float) – Real part of refractive index.
k (float = 0.0) – Imaginary part of refrative index.

Returns

Complex-valued relative permittivty.

Return type

complex

static nk_to_eps_sigma(n: float, k: float, freq: float) → Tuple[float, float]#

Convert n, k at frequency freq to permittivity and conductivity values.

Parameters

n (float) – Real part of refractive index.
k (float = 0.0) – Imaginary part of refrative index.
frequency (float) – Frequency to evaluate permittivity at (Hz).

Returns

Real part of relative permittivity & electric conductivity.

Return type

Tuple[float, float]

classmethod parse_file(path: Union[str, pathlib.Path], *, content_type: unicode = None, encoding: unicode = 'utf8', proto: pydantic.parse.Protocol = None, allow_pickle: bool = False) → Model#

classmethod parse_obj(obj: Any) → Model#

classmethod parse_raw(b: Union[str, bytes], *, content_type: unicode = None, encoding: unicode = 'utf8', proto: pydantic.parse.Protocol = None, allow_pickle: bool = False) → Model#

plot(freqs: float, ax: matplotlib.axes._axes.Axes = None) → matplotlib.axes._axes.Axes#

Plot n, k of a Medium as a function of frequency.

Parameters

freqs (float) – Frequencies (Hz) to evaluate the medium properties at.
ax (matplotlib.axes._subplots.Axes = None) – Matplotlib axes to plot on, if not specified, one is created.

Returns

The supplied or created matplotlib axes.

Return type

matplotlib.axes._subplots.Axes

classmethod schema(by_alias: bool = True, ref_template: unicode = '#/definitions/{model}') → DictStrAny#

classmethod schema_json(*, by_alias: bool = True, ref_template: unicode = '#/definitions/{model}', **dumps_kwargs: Any) → unicode#

sigma_model(freq: float) → complex#

Complex-valued conductivity as a function of frequency.

Parameters: freq (float) – Frequency to evaluate conductivity at (Hz).
Returns: Complex conductivity at this frequency.
Return type: complex

to_file(fname: str) → None#

Exports Tidy3dBaseModel instance to .yaml, .json, or .hdf5 file

Parameters: fname (str) – Full path to the .yaml or .json file to save the Tidy3dBaseModel to.

Example

>>> simulation.to_file(fname='folder/sim.json') 

to_hdf5(fname: str) → None#

Exports Tidy3dBaseModel instance to .hdf5 file.

Parameters: fname (str) – Full path to the .hdf5 file to save the Tidy3dBaseModel to.

Example

>>> simulation.to_hdf5(fname='folder/sim.hdf5') 

to_json(fname: str) → None#

Exports Tidy3dBaseModel instance to .json file

Parameters: fname (str) – Full path to the .json file to save the Tidy3dBaseModel to.

Example

>>> simulation.to_json(fname='folder/sim.json') 

to_yaml(fname: str) → None#

Exports Tidy3dBaseModel instance to .yaml file.

Parameters: fname (str) – Full path to the .yaml file to save the Tidy3dBaseModel to.

Example

>>> simulation.to_yaml(fname='folder/sim.yaml') 

classmethod tuple_to_dict(tuple_values: tuple) → dict#: How we generate a dictionary mapping new keys to tuple values for hdf5.

classmethod update_forward_refs(**localns: Any) → None#: Try to update ForwardRefs on fields based on this Model, globalns and localns.

updated_copy(**kwargs) → tidy3d.components.base.Tidy3dBaseModel#: Make copy of a component instance with **kwargs indicating updated field values.

classmethod validate(value: Any) → Model#

abstract property n_cfl#

To ensure a stable FDTD simulation, it is essential to select an appropriate time step size in accordance with the CFL condition. The maximal time step size is inversely proportional to the speed of light in the medium, and thus proportional to the index of refraction. However, for dispersive medium, anisotropic medium, and other more complicated media, there are complications in deciding on the choice of the index of refraction.

This property computes the index of refraction related to CFL condition, so that the FDTD with this medium is stable when the time step size that doesn’t take material factor into account is multiplied by n_cfl.