tidy3d.Sellmeier#

class tidy3d.Sellmeier#

Bases: tidy3d.components.medium.DispersiveMedium

A dispersive medium described by the Sellmeier model. The frequency-dependence of the refractive index is described by:

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.

  • coeffs (Tuple[Tuple[float, pydantic.types.PositiveFloat], ...]) – [units = (None, um^2)]. List of Sellmeier (\(B_i, C_i\)) coefficients.

Note

\[n(\lambda)^2 = 1 + \sum_i \frac{B_i \lambda^2}{\lambda^2 - C_i}\]

Example

>>> sellmeier_medium = Sellmeier(coeffs=[(1,2), (3,4)])
>>> eps = sellmeier_medium.eps_model(200e12)

Show JSON schema
{
   "title": "Sellmeier",
   "description": "A dispersive medium described by the Sellmeier model.\nThe frequency-dependence of the refractive index is described by:\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.\ncoeffs : Tuple[Tuple[float, pydantic.types.PositiveFloat], ...]\n    [units = (None, um^2)].  List of Sellmeier (:math:`B_i, C_i`) coefficients.\n\nNote\n----\n.. math::\n\n    n(\\lambda)^2 = 1 + \\sum_i \\frac{B_i \\lambda^2}{\\lambda^2 - C_i}\n\nExample\n-------\n>>> sellmeier_medium = Sellmeier(coeffs=[(1,2), (3,4)])\n>>> eps = sellmeier_medium.eps_model(200e12)",
   "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": "Sellmeier",
         "enum": [
            "Sellmeier"
         ],
         "type": "string"
      },
      "coeffs": {
         "title": "Coefficients",
         "description": "List of Sellmeier (:math:`B_i, C_i`) coefficients.",
         "units": [
            null,
            "um^2"
         ],
         "type": "array",
         "items": {
            "type": "array",
            "minItems": 2,
            "maxItems": 2,
            "items": [
               {
                  "type": "number"
               },
               {
                  "type": "number",
                  "exclusiveMinimum": 0
               }
            ]
         }
      }
   },
   "required": [
      "coeffs"
   ],
   "additionalProperties": false
}

attribute coeffs: Tuple[Tuple[float, pydantic.types.PositiveFloat], ...] [Required]#

List of Sellmeier (\(B_i, C_i\)) coefficients.

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.

static complex_to_tuple(value: complex) → Tuple[float, float]#

Convert a complex number to a tuple of real and imaginary parts.

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

eps_model(frequency: float) → complex#

Complex-valued permittivity as a function of frequency.

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_dispersion(n: float, freq: float, dn_dwvl: float = 0, **kwargs)#

Convert n and wavelength dispersion dn_dwvl values at frequency freq to a single-pole Sellmeier medium.

Parameters

  • n (float) – Real part of refractive index. Must be larger than or equal to one.

  • dn_dwvl (float = 0) – Derivative of the refractive index with wavelength (1/um). Must be negative.

  • freq (float) – Frequency at which n and dn_dwvl are sampled.

Returns

Single-pole Sellmeier medium with the prvoided refractive index and index dispersion valuesat at the prvoided frequency.

Return type

Sellmeier

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#
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')
static tuple_to_complex(value: Tuple[float, float]) → complex#

Convert a tuple of real and imaginary parts to complex number.

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#
property pole_residue#

Representation of Medium as a pole-residue model.