.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_demos/demo.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_auto_demos_demo.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_demos_demo.py:


Fresnel Propagator demo
=======================
This demo will compute and display the Fresnel transform of a given aperture.

.. GENERATED FROM PYTHON SOURCE LINES 6-13

.. code-block:: default


    import numpy as np
    from matplotlib import pyplot as plt
    from optics.propagators import FresnelPropagator
    from typing import Sequence









.. GENERATED FROM PYTHON SOURCE LINES 14-17

Build the aperture
------------------
First we define a circle function.

.. GENERATED FROM PYTHON SOURCE LINES 17-27

.. code-block:: default

    def circle(shape: Sequence[int], radius: float):
        """Create a circle of a given radius centered in an array of a given shape."""
        for dim in shape:
            assert radius < dim

        x, y = np.meshgrid(np.arange(shape[0]), np.arange(shape[1]))
        r = np.abs((x - (shape[0] - 1) / 2) ** 2 + (y - (shape[1] - 1) / 2) ** 2) < radius ** 2
        return r.astype('int')









.. GENERATED FROM PYTHON SOURCE LINES 28-29

Then we define some parameters and build the aperture.

.. GENERATED FROM PYTHON SOURCE LINES 29-44

.. code-block:: default

    input_shape = (300, 300)
    dx = (1e-2, 1e-2)
    z = 1e5
    wavelength = 1e-6

    aperture = circle(shape=input_shape, radius=50)
    aperture = aperture - circle(shape=input_shape, radius=10)
    diag_idx = np.diag_indices(300)
    aperture[diag_idx[0], diag_idx[1]] = 0
    aperture[np.flip(diag_idx[0]), diag_idx[1]] = 0

    plt.imshow(aperture)
    plt.title('Aperture')
    plt.show()




.. image-sg:: /auto_demos/images/sphx_glr_demo_001.png
   :alt: Aperture
   :srcset: /auto_demos/images/sphx_glr_demo_001.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 45-47

Call the Fresnel Propagator
---------------------------

.. GENERATED FROM PYTHON SOURCE LINES 47-56

.. code-block:: default

    fresnel_propagator = FresnelPropagator(
        input_shape=input_shape,
        dx=dx,
        z=z,
        wavelength=wavelength,
    )

    y = fresnel_propagator(aperture)








.. GENERATED FROM PYTHON SOURCE LINES 57-59

Plot the field at distance :math:`z`
-------------------------------------------------

.. GENERATED FROM PYTHON SOURCE LINES 59-66

.. code-block:: default


    fig, (ax1, ax2) = plt.subplots(1, 2)
    ax1.imshow(abs(y) ** 2)
    ax1.set_title("Intensity")
    ax2.imshow(np.angle(y))
    ax2.set_title("Phase")

    plt.show()


.. image-sg:: /auto_demos/images/sphx_glr_demo_002.png
   :alt: Intensity, Phase
   :srcset: /auto_demos/images/sphx_glr_demo_002.png
   :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  0.283 seconds)


.. _sphx_glr_download_auto_demos_demo.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example




    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: demo.py <demo.py>`

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: demo.ipynb <demo.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_