.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_tutorials/capillaries/plot_06_vector_raman.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_auto_tutorials_capillaries_plot_06_vector_raman.py>`
        to download the full example code.

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

.. _sphx_glr_auto_tutorials_capillaries_plot_06_vector_raman.py:


Follow vector Raman coherence with a delayed probe
==================================================

Compare equal-amplitude linear and circular envelopes using hydrogen's
rotational response. A fixed circular pump has one quarter of the rotational
source along its Jones direction. This is a local polarisation comparison,
not a pump-Stokes gain ratio or a propagated energy comparison.

An oblique pump also writes an off-diagonal molecular coherence. A later weak
x-polarised probe acquires a y-polarised Raman source after the pump has gone.
The calculation is deterministic and uses local electric fields in V/m;
no spontaneous Raman noise or complex modal basis is introduced.

.. GENERATED FROM PYTHON SOURCE LINES 19-65

.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from solprop.nonlinear.raman import MolecularOptions, response_for
    from solprop.physdata import MaterialSelection

    spacing = 0.5e-15
    time = np.arange(2048) * spacing
    density = 1e25
    response = response_for(
        "H2",
        MolecularOptions(vibration=False),
        selection=MaterialSelection(carrier_wavelength=800e-9),
        density=density,
    )
    pump = 2e8 * np.exp(-(((time - 100e-15) / 15e-15) ** 2))
    probe = 0.02 * 2e8 * np.exp(-(((time - 280e-15) / 15e-15) ** 2))
    linear = np.array([1.0, 0.0], complex)
    circular = np.array([1.0, 1j]) / np.sqrt(2)

    figure, axes = plt.subplots(1, 2, figsize=(10, 3.6), layout="constrained")
    for direction, label in ((linear, "Linear"), (circular, "Circular")):
        source = response.evaluate(
            direction[:, None] * pump, density, kind="envelope", dt=spacing
        )
        along = np.real(direction.conj() @ source)
        axes[0].plot(time * 1e15, along * 1e12, label=label)
    axes[0].set(xlim=(60, 145), xlabel="Time (fs)", ylabel="Source along launch (pC/m²)")
    axes[0].legend()

    # Subtract the pump-only response to show the weak probe's induced source.
    # The pump/probe separation is large compared with their widths, so their
    # instantaneous overlap is negligible. The off-diagonal history remains.
    oblique = np.array([1.0, 1.0])[:, None] * pump / np.sqrt(2)
    combined = oblique + linear[:, None] * probe
    induced = response.evaluate(combined, density, kind="envelope", dt=spacing)
    induced -= response.evaluate(
        oblique.astype(complex), density, kind="envelope", dt=spacing
    )
    for component, label in enumerate(("Along probe (x)", "Cross-polarised (y)")):
        axes[1].plot(time * 1e15, np.real(induced[component]) * 1e12, label=label)
    axes[1].set(xlim=(235, 325), xlabel="Time (fs)", ylabel="Probe-induced source (pC/m²)")
    axes[1].legend()
    plt.show()




.. image-sg:: /auto_tutorials/capillaries/images/sphx_glr_plot_06_vector_raman_001.png
   :alt: plot 06 vector raman
   :srcset: /auto_tutorials/capillaries/images/sphx_glr_plot_06_vector_raman_001.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    /home/docs/checkouts/solprop/checkouts/24/src/solprop/nonlinear/optmat_raman.py:1121: MaterialRangeWarning: H2: optmat's Raman response raman_response/H2@293.15K,800nm is used outside its validated density range (0.3722 to 0.3722 amagat). optmat: density below 0.94 amagat, where the motion of the molecules sets the widths: the Dicke terms are capped at the Doppler widths (TC-688)
      densities = _check_range(response, request)




.. GENERATED FROM PYTHON SOURCE LINES 66-72

Related reading
---------------
Continue with :doc:`/guide/media/raman-vector` for the model, options and limits,
and :doc:`/guide/numerics/accuracy` for convergence checks.
For a paced propagation lesson, return to
:doc:`/introduction/lessons/plot_01_rdw`.


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

   **Total running time of the script:** (0 minutes 0.236 seconds)


.. _sphx_glr_download_auto_tutorials_capillaries_plot_06_vector_raman.py:

.. only:: html

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

      :download:`Download Python source code: plot_06_vector_raman.py <plot_06_vector_raman.py>`

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

      :download:`Download zipped: plot_06_vector_raman.zip <plot_06_vector_raman.zip>`