.. _const-material:

Constant Material Model
========================================

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Overview
---------------

The :class:`ConstMaterial <pyOptiShared.Material.ConstMaterial>` class represents a simple, non-dispersive material 
with a constant complex relative permittivity. This model is useful 
for electromagnetic simulations, when a simple, non-dispersive description of the material properties is required.

This class can be used to assign material properties to simulation domains 
such as waveguides, substrates, or claddings where permittivity does not change 
with frequency.

Examples
--------------

**Instantiating a Constant Material Object:**

.. code-block:: python

    from pyOptiShared.Material import ConstMaterial

    material = ConstMaterial("my_material", epsReal=3.45, epsImag=0.001)

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

Usage Notes
--------------

- This material assumes isotropic conditions.
- For narrowband analysis, loss can be supported via a complex term in the constant model. However, an analytic dispersive model is  recommended to prevent violating Krammers-Kronig relations.
- For more complex materials (e.g., lossy and dispersive), consider using an alternative model like :ref:`sellmeier-material` or :ref:`experimental-material`.