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

.. only:: html

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

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

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

.. _sphx_glr_gallery_interpretation_phase_function_size_regimes.py:


See how particle size reshapes angular scattering
=================================================

Total scattering efficiency cannot describe where the scattered power goes.
This example compares normalized unpolarized phase functions for three sphere
diameters at the same wavelength. As the size parameter increases, the forward
lobe narrows and the angular pattern develops more structure.

Each curve integrates to one over solid angle, so the plot compares angular
redistribution rather than total scattered power. The legend also reports
``Qsca`` and the asymmetry factor ``g`` to retain both pieces of information.

.. GENERATED FROM PYTHON SOURCE LINES 14-60



.. image-sg:: /gallery/interpretation/images/sphx_glr_phase_function_size_regimes_001.png
   :alt: Equal-area phase functions reveal angular redistribution
   :srcset: /gallery/interpretation/images/sphx_glr_phase_function_size_regimes_001.png
   :class: sphx-glr-single-img





.. code-block:: Python

    import matplotlib.pyplot as plt
    import numpy as np

    from PyMieSim import Measure, PlaneWave, PolarizationState, Simulation, Sphere, ureg

    wavelength = 532 * ureg.nanometer
    angles = np.linspace(0, np.pi, 1201)
    source = PlaneWave(
        wavelength=wavelength,
        polarization=PolarizationState(angle=0 * ureg.degree),
        amplitude=1 * ureg.volt / ureg.meter,
    )

    figure, axis = plt.subplots(figsize=(8.5, 5.2))
    for diameter in (80, 300, 1000):
        simulation = Simulation(
            scatterer=Sphere(
                diameter=diameter * ureg.nanometer,
                material=1.59,
                medium=1.33,
            ),
            source=source,
        )
        s1, s2 = simulation.get_s1s2(angles=angles * ureg.radian)
        intensity = (np.abs(s1.magnitude) ** 2 + np.abs(s2.magnitude) ** 2) / 2
        normalization = 2 * np.pi * np.trapezoid(intensity * np.sin(angles), angles)
        phase_function = intensity / normalization
        qsca = simulation.get(Measure.QSCA).magnitude
        asymmetry = simulation.get(Measure.G).magnitude
        axis.semilogy(
            np.rad2deg(angles),
            phase_function,
            linewidth=2,
            label=f"d = {diameter} nm   |   Qsca = {qsca:.2f}, g = {asymmetry:.2f}",
        )

    axis.set(
        xlabel="Scattering angle [degrees]",
        ylabel="Normalized phase function [sr⁻¹]",
        xlim=(0, 180),
        title="Equal-area phase functions reveal angular redistribution",
    )
    axis.set_xticks(np.arange(0, 181, 30))
    axis.grid(alpha=0.2)
    axis.legend()
    plt.show()


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

   **Total running time of the script:** (0 minutes 0.165 seconds)


.. _sphx_glr_download_gallery_interpretation_phase_function_size_regimes.py:

.. only:: html

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

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

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

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

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

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: phase_function_size_regimes.zip <phase_function_size_regimes.zip>`


.. only:: html

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

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