CoreShell: Qback vs Core Diameter

This example demonstrates how to compute and visualize the backscattering efficiency (Qback) as functions of core diameter for CoreShell scatterers using PyMieSim.

import PyOptik
from PyMieSim import from_pyoptik

Importing the package dependencies: numpy, PyMieSim

import numpy
from PyMieSim import (
    Measure,
    ureg,
    CoreShellSet,
    GaussianSet,
    PolarizationSet,
    Experiment,
)



polarization_set = PolarizationSet(
    angles=[0.0] * ureg.degree,
)

source = GaussianSet(
    wavelength=[800, 900, 1000] * ureg.nanometer,
    polarization=polarization_set,
    optical_power=[1e-3] * ureg.watt,
    numerical_aperture=[0.2],
)

scatterer = CoreShellSet(
    core_diameter=numpy.geomspace(100, 900, 400) * ureg.nanometer,
    shell_thickness=[800] * ureg.nanometer,
    core_material=[from_pyoptik(PyOptik.load_material(name="main/Ag/Johnson"))],
    shell_material=[from_pyoptik(PyOptik.load_material(name="specs/SCHOTT-optical/P-BK7"))],
    medium=[from_pyoptik(PyOptik.load_material(name="main/H2O/Daimon-19.0C"), medium=True)],
)

experiment = Experiment(scatterer_set=scatterer, source_set=source)

result = experiment.get(Measure.QBACK)

print("Result dimensions and shape:", result.dims, result.shape)
print("Measure units:", result.attrs["units"])

result.plot(x="scatterer:core_diameter")

Result dimensions and shape: ('source:wavelength', 'scatterer:core_diameter') (3, 400)
Measure units: {'Qback': <Unit('dimensionless')>}