.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "examples/simple_propagation.py"
.. LINE NUMBERS ARE GIVEN BELOW.
.. only:: html
.. note::
:class: sphx-glr-download-link-note
:ref:`Go to the end <sphx_glr_download_examples_simple_propagation.py>`
to download the full example code
.. rst-class:: sphx-glr-example-title
.. _sphx_glr_examples_simple_propagation.py:
Simple propagation
==================
Basic example of physical optics propagation through a simple optical system
consisting of a square aperture illuminated by a point source and focused by
a thin lens.
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Import libraries required for simulation
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.. code-block:: default
import matplotlib.pyplot as plt
import numpy as np
import pysrw as srw
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Create the wavefront arriving at the first plane of the optical system as
described in :doc:`point_source`. Check the section about propagation for
some tips about the definition of the mesh parameters.
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.. code-block:: default
ptSrc = srw.emitters.PointSource()
observer = srw.wavefronts.Observer(centerCoord=[0, 0, .5],
obsXextension=10e-3,
obsYextension=10e-3,
obsXres=1e-6,
obsYres=1e-6)
wfr = srw.computePtSrcWfr(ptSrc, observer, wavelength=600)
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We use a basic optical system consisting of a square aperture and a thin lens
and we observe the intensity at the image plane of the lens.
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.. code-block:: default
w = 500e-6
f = 50e-3
s1 = observer.zPos
s2 = s1 * f / (s1 - f)
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The optical system is created as a dictionary representing the three optical
elements. Note that "aperture", "lens" and "image" are arbitrary names. The
nature of each optical element is defined by its "type" key
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.. code-block:: default
optSystem = {
"aperture": {
"type": "rectAp",
"extension": [w, w],
"centre": [0,0]
},
"lens": {
"type": "lens",
"f": f,
"centre": [0,0]
},
"image": {
"type": "drift",
"length": s2
}
}
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The propagation is performed using the
:py:func:`~pysrw.computations.propagateWfr` function. Since we leave all
optional arguments to their default values, the sequence ["lens", "drift"]
will be grouped, the intensity stored on all planes and the wavefront only
at the last "image" plane.
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.. code-block:: default
propData = srw.propagateWfr(wfr, optSystem)
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We plot the resulting intensity distribution at the "aperture" and
"image" planes
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.. code-block:: default
srw.plotI(propData["aperture"]["intensity"])
srw.plotI(propData["image"]["intensity"])
.. rst-class:: sphx-glr-horizontal
*
.. image-sg:: /examples/images/sphx_glr_simple_propagation_001.png
:alt: simple propagation
:srcset: /examples/images/sphx_glr_simple_propagation_001.png
:class: sphx-glr-multi-img
*
.. image-sg:: /examples/images/sphx_glr_simple_propagation_002.png
:alt: simple propagation
:srcset: /examples/images/sphx_glr_simple_propagation_002.png
:class: sphx-glr-multi-img
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As expected, the final spot is much smaller with respect to the simulated
wavefront. The extended wavefront is necessary at the entrance of the optical
system, to leave enough margin around the aperture. However, the extension
can be significantly reduced at the image plane, as the light is focused by
the lens. This can be achieved by adding some resize parameters to reduce
by a factor 10 the extension and increase by a factor 2 the resolution to
obtain a smoother profile
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.. code-block:: default
optSystem["image"]["resParam"] = {"hRangeChange": 1/10, "hResChange": 2.0,
"vRangeChange": 1/10, "vResChange": 2.0,
"hCentreChange": 0.0, "vCentreChange": 0.0}
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The computation is then repeated. To save time and memory, we store the
intensity only at the final "image" plane
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.. code-block:: default
propData = srw.propagateWfr(wfr, optSystem, saveIntAt=["image"])
srw.plotI(propData["image"]["intensity"])
.. image-sg:: /examples/images/sphx_glr_simple_propagation_003.png
:alt: simple propagation
:srcset: /examples/images/sphx_glr_simple_propagation_003.png
:class: sphx-glr-single-img
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We can finally extract a profile and compare the simulated pattern with the
sinc profile of the diffraction from a rectangular aperture
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.. code-block:: default
cuts = srw.extractCrossCuts(propData["image"]["intensity"])
yax = cuts["yax"]
int_srw = cuts["ydata"]
int_theo = np.sinc(w * yax / (s2 * wfr.wavelength*1e-9))**2
fig, ax = plt.subplots()
ax.plot(yax*1e3, int_srw / np.max(int_srw))
ax.plot(yax*1e3, int_theo, label="theo", linestyle="--")
ax.set_xlabel("y position [mm]")
ax.set_ylabel("Intensity [arb. unit]")
ax.legend()
plt.show()
plt.tight_layout()
.. image-sg:: /examples/images/sphx_glr_simple_propagation_004.png
:alt: simple propagation
:srcset: /examples/images/sphx_glr_simple_propagation_004.png
:class: sphx-glr-single-img
.. rst-class:: sphx-glr-timing
**Total running time of the script:** (1 minutes 41.740 seconds)
**Estimated memory usage:** 4596 MB
.. _sphx_glr_download_examples_simple_propagation.py:
.. only:: html
.. container:: sphx-glr-footer sphx-glr-footer-example
.. container:: sphx-glr-download sphx-glr-download-python
:download:`Download Python source code: simple_propagation.py <simple_propagation.py>`
.. container:: sphx-glr-download sphx-glr-download-jupyter
:download:`Download Jupyter notebook: simple_propagation.ipynb <simple_propagation.ipynb>`
.. only:: html
.. rst-class:: sphx-glr-signature
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