`PDielec.Materials`#

Materials DataBase.

An interface to the spreadsheet which holds materials data

Module Contents#

Classes#

`Constant`	A class representing a material with constant scalar permittivity, inheriting from the Material class.
`DrudeLorentz`	A subclass representing a material with a Lorentz-Drude model permittivity.
`External`	A class for representing materials with externally specified permittivity.
`FPSQ`	Class representing a material with a FPSQ model for permittivity.
`Material`	A class for representing materials with properties like name, density, permittivity, and unit cell.
`MaterialsDataBase`	A class for managing a database of materials' properties.
`Sellmeier`	A class to define materials using the Sellmeier model for permittivity.
`Tabulated`	A class for materials with tabulated permittivities.

class PDielec.Materials.Constant(name, permittivity=None, density=None, cell=None)[source]#

Bases: Material

A class representing a material with constant scalar permittivity, inheriting from the Material class.

Attributes#

typestr: The type of material, set to ‘Constant permittivity’.

Methods#

Inherits methods from the Material class.

class PDielec.Materials.DrudeLorentz(name, epsinf, omegas, strengths, gammas, density=None, cell=None)[source]#

Bases: Material

A subclass representing a material with a Lorentz-Drude model permittivity.

Parameters#

namestr: The name of the material.
epsinfarray_like: Epsilon infinity, either a 3x3 list or a 3x3 array representing the static dielectric constant.
omegaslist: The transverse optical (TO) frequencies.
strengthslist: The oscillator strengths for each resonance.
gammaslist: The damping (or broadening) factors for each resonance.
densityfloat, optional: The density of the material in grams per milliliter (g/ml). Default is None.
cellunitCell, optional: The unit cell of the material. Default is None.

Notes#

The Drude-Lorentz model is used to calculate the permittivity of the material by considering the contributions from both free electrons (Drude) and bound electrons (Lorentz). This class requires specifying the infinite frequency dielectric constant (epsinf), the transverse optical frequencies (omegas), the oscillator strengths (strengths), and the damping factors (gammas) for each resonance in the material.

Examples#

>>> drude_lorentz_material = DrudeLorentz("Gold", [[1, 0, 0], [0, 1, 0], [0, 0, 1]],
...                                       [0.5, 1.0], [1.0, 2.0], [0.2, 0.1],
...                                       density=19.3)
This represents a Drude-Lorentz material with the name "Gold", an isotropic epsilon infinity,
two resonances with specified frequencies, strengths, and damping factors, and
a density of 19.3 g/ml.

class PDielec.Materials.External(name, permittivityObject=None, density=None, cell=None)[source]#

Bases: Material

A class for representing materials with externally specified permittivity.

This class inherits from the Material class and is used to define materials where the permittivity is specified externally, rather than calculated or predefined. Permittivity can be a complex value indicating both the real and imaginary parts.

class PDielec.Materials.FPSQ(name, epsinf, omega_tos, gamma_tos, omega_los, gamma_los, density=None, cell=None)[source]#

Bases: Material

Class representing a material with a FPSQ model for permittivity.

Parameters#

namestr: The name of the material.
epsinfarray_like: Epsilon infinity (eps0), either a 3x3 list or a 3x3 array representing the dielectric constant at infinite frequency.
omega_toslist: The transverse optical (TO) frequencies.
gamma_toslist: The TO absorption widths.
omega_loslist: The longitudinal optical (LO) frequencies.
gamma_loslist: The LO absorption widths.
densityfloat, optional: The density of the material in grams per milliliter (g/ml).
cellunitCell, optional: The unit cell of the material.

Notes#

The FPSQ (fitted phonon simple quantum) model is used to describe the permittivity of the material. This model is based on the harmonic oscillator model and describes the permittivity as a function of frequency.

class PDielec.Materials.Material(name, density=None, permittivityObject=None, cell=None)[source]#

A class for representing materials with properties like name, density, permittivity, and unit cell.

The Material class also contains the permittivity object for the material. The permittivity object is an instance of DielectricFunction or one its children. The permittivity object is responsible for calculating the permittivity at the given frequency. The subclasses which inherit from the Material class are: Constant, External, DrudeLorentz, FPSQ, Sellmeier, and Tabulated. Each subclass has an initialisation routine which instantiates the permittivity object of the appropriate type for the material. The relationship between the Material subclass and the DielectricFunction subclass of the permittivity object is shown below.

Material subclass	DielectricFunction subclass
Material subclass	DielectricFunction subclass
`Constant`	`Constant`
`Constant`	`Constant`
`External`	This class is passed a permittivity object which has been defined externally


`DrudeLorentz`	`DrudeLorentz`
`DrudeLorentz`	`DrudeLorentz`
`FPSQ`	`FPSQ`
`FPSQ`	`FPSQ`
`Sellmeier`	`Sellmeier`
`Sellmeier`	`Sellmeier`
`Tabulated`	`TabulateScalar` `Tabulate3` `Tabulate3` `Tabulate6`

Parameters#

namestr: The name of the material.
densityfloat, optional: The density of the material. If not provided and a cell is given, it will be calculated based on the cell.
permittivityObjectDielectricFunction, optional: An object representing the dielectric function of the material. This is intended to be passed by classes that inherit from Material, and it should contain methods for calculating scalar/tensor permittivity. (see DielectricFunction and its sub-classes)
cellUnitCell, optional: An object representing the unit cell of the material. If provided without a density, the density will be calculated from this cell. (See UnitCell)

Attributes#

densityfloat: The density of the material, which may be calculated based on the cell if not provided initially.
cellCell or None: The unit cell of the material if provided.
namestr: The name of the material.
typestr: A string indicating the type of the object. Defaults to ‘Base Class’ for the base Material class.
permittivityObjectDielectricFunction or None: An object to handle the permittivity calculations for the material.

Methods#

getName(): Returns the name of the material.
getInformation(): Returns information about the material, including its type and, if applicable, its permittivity frequency range.
getSigmas(): If the material has a lorentzian dielectric this routine returns the sigma parameters
setSigmas(): If the material has a lorentzian dielectric this routine sets the sigma parameters
getFrequencies(): If the material has a lorentzian dielectric this routine returns the frequencies
setFrequencies(): If the material has a lorentzian dielectric this routine sets the frequencies
getOscillatorStrengths(): If the material has a lorentzian dielectric this routine returns the oscillator strengths
setOscillatorStrengths(): If the material has a lorentzian dielectric this routine sets the oscillator strengths
print(): Prints information about the material, such as its name, density, type, and permittivity details.
isScalar(): Checks and returns True if the material’s permittivity is scalar.
isTensor(): Checks and returns True if the material’s permittivity is tensor.
getPermittivityObject(): Returns the permittivityObject of the material.
getPermittivityFunction(): Returns the permittivity function from the permittivityObject.
getDensity(): Returns the density of the material.
setCell(cell): Sets the cell of the material and updates the density if it was initially None.
getCell(): Returns the cell of the material.
setDensity(value): Sets the density of the material.
setEpsilonInfinity(eps): Sets the epsilon infinity of the material
setPermittivityObject(permittivityObject): Sets the permittivityObject for the material.

getCell()[source]#: Return the cell.

Parameters#

None

Returns#

self.cell

getDensity()[source]#: Return the density.

Parameters#

None

Returns#

self.density

getFrequencies()[source]#

Get the frequencies for a Lorentzian permittivity.

Parameters#

None

Returns#

1d array of floats: Returns the frequencies for a Lorentzian function in cm-1

getInformation()[source]#

Return information about the material.

Parameters#

None

Returns#

str: A description of the material.

getName()[source]#

Get the name attribute of the object.

Parameters#

None

Returns#

str: The name attribute of the object.

bool: True if the material returns a tensor permittivity, False otherwise.

print()[source]#: Print information about the material.

Parameters#

None

Returns#

None

setCell(cell)[source]#

Set the unit cell.

Parameters#

cella unit cell: Set the unit cell of the material

Returns#

None

setDensity(value)[source]#

Set the density.

Parameters#

valuefloat: The value of the density

Returns#

None

setFrequencies(frequencies)[source]#

Set the frequencies for a Lorentzian permittivity.

Parameters#

frequencies1D array of floats: The frequencies for a Drude-Lorentzian permittivity in cm-1

Returns#

None

setOscillatorStrengths(strengths)[source]#

Set the oscillator strengths for a Lorentzian permittivity.

Parameters#

strengthsa 3x3 array of floats for each frequency: The oscillator strengths for a Lorentzian permittivity function in cm-1

Returns#

None

setPermittivityObject(permittivityObject)[source]#

Set the permittivity object.

Parameters#

permittivityObjecta permittivity object (dielectric function object): The permittivity object is used to calculate the permittivity of the material

Returns#

None

setSigmas(sigmas)[source]#

Set the sigma parameters for a Lorentzian permittivity.

Parameters#

sigmas1D array of floats: The sigma parameters for a Lorentzian permittivity function in cm-1

Returns#

None

class PDielec.Materials.MaterialsDataBase(filename, debug=False)[source]#

A class for managing a database of materials’ properties.

This database is initialized from an Excel spreadsheet which contains various material properties including names, densities, refractive indices, and permittivities, among others. Additional functionalities include validation checks, retrieval of sheet names, material information, and specific data based on the property of interest (e.g., constant permittivity, tabulated refractive index). The getMaterial() method returns a material with a dielectric function of the appropriate type. There are routines which read (process) the data stored for the following dielectric functions:

constant refractive index
constant permittivity
tabulated refractive index (may be 1, 3 or 6 parameters for isotropic, uniaxial or anisotropic)
tabulated permittivity (may be 1, 3 or 6 parameters for isotropic, uniaxial or anisotropic)
Lorentz-Drude
FPSQ (Four parameters semi-quantum model)
Sellmeier

Further information can be found in the following classes and their sub-classes:

Parameters#

filenamestr: The filename of the spreadsheet/database.
debugbool, optional: Set to true for additional debugging information

Attributes#

filenamestr: The path to the Excel spreadsheet containing materials data.
sheetNameslist: A list of strings representing the names of the sheets within the Excel spreadsheet.
cachedictionary: A dictionary of materials that have been read from the database
debugbool, optional: A flag indicating whether debugging information should be printed. Default is False.

Methods#

__init__(filename, debug=False): Initializes the MaterialsDataBase class with a given Excel spreadsheet and a debug flag.
getFileName(): Returns the filename of the Excel spreadsheet being used as the database.
valid(): Checks if the spreadsheet is a valid materials database based on certain criteria.
getSheetNames(): Retrieves a sorted list of sheet names within the spreadsheet, including additional predefined names.
getMaterial(sheet): Returns a material object based on the data in a given sheet of the Excel spreadsheet.
readConstantRefractiveIndex(sheet, worksheet, density): Reads constant refractive index data for a given material from the spreadsheet.
readConstantPermittivity(sheet, worksheet, density): Reads constant permittivity data for a given material from the spreadsheet.
readTabulatedRefractiveIndex(sheet, worksheet, density): Reads tabulated refractive index data for a given material from the spreadsheet.
readTabulatedPermittivity(sheet, worksheet, density): Reads tabulated permittivity data for a given material from the spreadsheet.
readLorentzDrude(sheet, worksheet, density, unitCell): Reads Drude-Lorentz model parameters for a given material from the spreadsheet.
readFPSQ(sheet, worksheet, density, unitCell): Reads FPSQ model parameters for a given material from the spreadsheet.
readSellmeier(sheet, worksheet, density, unitCell): Reads Sellmeier model parameters for a given material from the spreadsheet.

getFileName()[source]#

Return the filename.

Parameters#

None

Returns#

str: The filename.

getMaterial(sheet)[source]#

Return a material object based on the data in sheet (an excel sheet).

If one of the following is requested: air, vacuum, ptfe, ldpe, mdpe, kbr, nujol, then the material is created even if it is not in the database.

Parameters#

sheetExcel sheet: The excel sheet containing the material data.

Returns#

Material object: The material object created from the excel sheet data.

getSheetNames()[source]#

Return a list of the sheetnames in the database.

As well as the sheets in the database, there are some default materials which will be added to the list of materials and which are provided internally by this module.

Parameters#

None

Returns#

list: A list of the sheet names present in the database.

readConstantPermittivity(sheet, worksheet, density)[source]#

Read constant permittivity data from the spreadsheet.

Parameters#

sheetstr: The worksheet name.
worksheetworksheet: The worksheet instance.
densityfloat: The density of the material.

Returns#

None

readConstantRefractiveIndex(sheet, worksheet, density)[source]#

Read constant refractive index from the spreadsheet.

Parameters#

sheetstr: The worksheet name.
worksheetworksheet: The worksheet.
densityfloat: The density of the material.

Returns#

None

readFPSQ(sheet, worksheet, density, unitCell)[source]#

Read FPSQ data from the spreadsheet.

Parameters#

sheetstr: The worksheet name.
worksheetworksheet: The actual worksheet object.
densityfloat: The density of the material.
unitCellobject: The unit cell.

Returns#

None

readLorentzDrude(sheet, worksheet, density, unitCell)[source]#

Read Drude-Lorentz data from the spreadsheet.

Parameters#

sheetstr: The worksheet name.
worksheetworksheet: The worksheet.
densityfloat: The density of the material.
unitCellobject: The unit cell.

Returns#

None

readSellmeier(sheet, worksheet, density, unitCell)[source]#

Read Sellmeier data from the spreadsheet.

Parameters#

sheetstr: The worksheet name.
worksheetworksheet: The worksheet.
densityfloat: The density of the material.
unitCellobject: The unit cell.

Returns#

None

readTabulatedPermittivity(sheet, worksheet, density)[source]#

Read tabulated permittivity data from the spreadsheet.

Parameters#

sheetstr: The worksheet name.
worksheetworksheet: The worksheet.
densityfloat: The density of the material.

Returns#

None

readTabulatedRefractiveIndex(sheet, worksheet, density)[source]#

Read tabulated refractive index data from the spreadsheet.

Parameters#

sheetstr: The worksheet name.
worksheetworksheet: The worksheet.
densityfloat: The density of the material.

Returns#

None

valid()[source]#

Test to see if the spreadsheet is a valid materials database.

Parameters#

None

Returns#

bool: True if the spreadshee is ‘valid’

Notes#

None

class PDielec.Materials.Sellmeier(name, Bs, Cs, density=None, cell=None)[source]#

Bases: Material

A class to define materials using the Sellmeier model for permittivity.

Parameters#

namestr: The name of the material.
Bslist or array_like: The B parameters (coefficients) in the Sellmeier equation.
Cslist or array_like: The C parameters (coefficients) in the Sellmeier equation.
densityfloat, optional: The density of the material in g/ml. Default is None.
cellunitCell, optional: The unit cell of the material. Default is None.

Attributes#

typestr: The type of the material, which is ‘Sellmeier’ for instances of this class.

Methods#

__init__(self, name, Bs, Cs, density=None, cell=None): Initializes a Sellmeier material with specified parameters.

class PDielec.Materials.Tabulated(name, vs_cm1=None, permittivities=None, density=None, cell=None)[source]#

Bases: Material

A class for materials with tabulated permittivities.

Parameters#

namestr: The name of the material.
vs_cm1list or None, optional: The list of tabulated frequencies in cm-1. Defaults to None.
permittivitiesarray-like or None, optional: The permittivities, either as a single vector (n,) or a tensor (3,n) or (6,n) for more complex materials. Defaults to None.
densityfloat or None, optional: The density of the material in g/ml. Defaults to None.
cellunitCell or None, optional: The unit cell of the material. Defaults to None.

Notes#

This class is designed to handle materials with a constant permittivity as well as those requiring more complex permittivity tensors.
The permittivity can be defined using either a scalar for simple materials or tensors for materials that require a support matrix.
The constructor converts the input lists of frequencies (vs_cm1) and permittivities into numpy arrays, and then generates the appropriate permittivity object depending on the complexity of the material’s permittivities.

Examples#

>>> material1 = Tabulated("Quartz", vs_cm1=[500, 1000, 1500], permittivities=[2.1, 2.3, 2.5], density=2.65)
>>> material2 = Tabulated("Synthetic", vs_cm1=[200, 400, 600], permittivities=[[2.1, 2.3, 2.5], [2.4, 2.6, 2.8], [3.0, 3.2, 3.4]], density=1.5)

setEpsilonInfinity(eps)[source]#

Set the value of epsilon infinity for the material.

Parameters#

epsfloat or 3x3 np array: The epsilon infinity tensor. If a single float then an isotropic 3x3 np array is created

Returns#

None

PDielec.Materials#

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`PDielec.Materials`#