.. _experimental-material:

Experimental Material Model
=============================

.. contents::
   :local:
   :depth: 2
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Overview
---------

The :class:`ExperimentalMaterial <pyOptiShared.Material.ExperimentalMaterial>` describes the frequency-dependent refractive index of a material using experimental data. 
This model relies on the user input of measurement data that can be done by:

- Passing an array of *values* and *wavelengths* when instantiating the class.
- Reading from a text file with columns (wl, n, k) or (wl, eps_real, eps_imag)
- Importing from `RefractiveIndex.info <https://refractiveindex.info/>`_ based on *shelf/book/page* values.




Examples
---------

Instantiating from Permittivity Array Data
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In this case the values are by default **permittivity** values.

.. code-block:: python

    from pyOptiShared.Material import ExperimentalMaterial

    wavelength = [1500, 1550, 1600]
    values = [1.3, 1.31, 1.32]

    material = ExperimentalMaterial("my_material", wavelength, values)

    wavelength = [1515, 1560, 1590]
    print(material.eps(wavelength))
    print(np.square(material.index(wavelength)))

Instantiating from Permittivity Text File
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In this case the values are by default **permittivity** values defined in a text file.

Content of the ``my_material.txt``:
::

    wl  epsr    epsi
    1500    1.2 0.0001
    1510    1.21 0.00011
    1520    1.22 0.00012
    1530    1.23 0.00013
    1540    1.24 0.00014
    1550    1.25 0.00015
    

.. code-block:: python

    import numpy as np
    from pyOptiShared.Material import ExperimentalMaterial

    material = ExperimentalMaterial("my_material")

    material.LoadText("my_material")

    wavelength = [1510, 1520, 1550]
    print(material.eps(wavelength))
    print(np.square(material.index(wavelength)))

Instantiating from RefractiveIndex.info
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This examples shows how load the information from `RefractiveIndex.info <https://refractiveindex.info/>`_
to set the permittivity values of material defined by *shelf/book/page* values. This values can be consulted
directly on `RefractiveIndex.info <https://refractiveindex.info/>`_ webpage.

.. code-block:: python

    import numpy as np
    from pyOptiShared.Material import ExperimentalMaterial

    material = ExperimentalMaterial("my_material")

    material.SetFromRefDotInfo(shelf="main", book="SiO2", page="Malitson", wavelength_unit=1e-9)

    print(material.eps([1500, 1550, 1600]))
    print(np.square(material.index([1500, 1550, 1600])))