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qiu_classical_simulation.wave_optics.classical_numerics

Classical references of a lens experiment: split-step numerics and thin lens analytics.

Functions:

propagate_exactly 

propagate_exactly(state: NDArray[complex128], parameters: ExperimentParameters, distance: float) -> NDArray[complex128]

Return a field after a free propagation over a distance in vacuum.

Source code in packages/qiu-classical-simulation/src/qiu_classical_simulation/wave_optics/classical_numerics.py 
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def propagate_exactly(
    state: npt.NDArray[np.complex128], parameters: ExperimentParameters, distance: float
) -> npt.NDArray[np.complex128]:
    """Return a field after a free propagation over a distance in vacuum."""
    signal = free_space_propagator_phase(
        parameters.k_axis, distance, parameters.vacuum_wavelength
    )
    return from_angular_spectrum(np.exp(1j * signal.data) * to_angular_spectrum(state))

classical_numerics_simulation 

classical_numerics_simulation(parameters: ExperimentParameters, propagation_after_lens: float) -> NDArray[complex128]

Return the exact split-step field at a distance behind the lens.

The same slicing of the lens as the simulations, with the phases and propagations applied exactly, and a single propagation behind the lens.

Parameters:

Returns:

Source code in packages/qiu-classical-simulation/src/qiu_classical_simulation/wave_optics/classical_numerics.py 
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def classical_numerics_simulation(
    parameters: ExperimentParameters, propagation_after_lens: float
) -> npt.NDArray[np.complex128]:
    """Return the exact split-step field at a distance behind the lens.

    The same slicing of the lens as the simulations, with the phases and propagations
    applied exactly, and a single propagation behind the lens.

    Args:
        parameters: The experiment.
        propagation_after_lens: The distance behind the lens.

    Returns:
        The normalized field.
    """
    state = parameters.initial_state
    for signal in parameters.ordered_lens_signals:
        if has_phase(signal):
            state = state * np.exp(1j * signal.data)
        state = propagate_exactly(state, parameters, parameters.lens_slice_thickness)
    return propagate_exactly(state, parameters, propagation_after_lens)

thin_lens_simulation 

thin_lens_simulation(parameters: ExperimentParameters, propagation_before_lens: float, propagation_after_lens: float) -> NDArray[float64]

Return the analytic Gaussian profile behind an ideal thin lens of the same focus.

Parameters:

  • parameters (ExperimentParameters) –

    The experiment.

  • propagation_before_lens (float) –

    The distance from the beam's waist to the thin lens.

  • propagation_after_lens (float) –

    The distance behind the thin lens.

Returns:

Source code in packages/qiu-classical-simulation/src/qiu_classical_simulation/wave_optics/classical_numerics.py 
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def thin_lens_simulation(
    parameters: ExperimentParameters,
    propagation_before_lens: float,
    propagation_after_lens: float,
) -> npt.NDArray[np.float64]:
    """Return the analytic Gaussian profile behind an ideal thin lens of the same focus.

    Args:
        parameters: The experiment.
        propagation_before_lens: The distance from the beam's waist to the thin lens.
        propagation_after_lens: The distance behind the thin lens.

    Returns:
        The normalized magnitude of the field.
    """
    _, beam_radius = beam_after_thin_lens(
        parameters.gaussian_beam_waist,
        propagation_after_lens,
        parameters.focal_length,
        parameters.vacuum_wavelength,
        refractive_index=1,
        distance_from_waist=propagation_before_lens,
    )
    profile = gaussian_signal(parameters.x_axis, beam_radius, parameters.gaussian_mean)
    return np.asarray(profile.to_signal().normalized_data, dtype=np.float64)