Scattering efficiency of a sphere

PyMieSim makes it easy to create a source and a scatterer. With these objects defined, it is possible to use PyMieSim to find the scattering efficiency of the scatterer. This feature can be used to plot a graph of the scattering efficiency of a sphere as a function of the permittivity and the size parameter.

Importing the package: PyMieSim

import numpy
from TypedUnit import ureg
import matplotlib.pyplot as plt

from PyMieSim.experiment.scatterer import Sphere
from PyMieSim.experiment.source import Gaussian
from PyMieSim.experiment import Setup


permitivity = numpy.linspace(-10, 50, 400)

index = numpy.sqrt(permitivity.astype(complex)) * ureg.RIU

diameter = numpy.linspace(1, 200, 400) * ureg.nanometer

source = Gaussian(
    wavelength=400 * ureg.nanometer,
    polarization=90 * ureg.degree,
    optical_power=1e-3 * ureg.watt,
    NA=0.2 * ureg.AU,
)


scatterer = Sphere(
    diameter=diameter, property=index, medium_property=1 * ureg.RIU, source=source
)

experiment = Setup(scatterer=scatterer, source=source)

data = (
    experiment.get("Qsca", add_units=False)
    .squeeze()
    .values.reshape([permitivity.size, diameter.size])
)

figure, ax = plt.subplots(1, 1)
ax.set(
    xlabel="Permittivity",
    ylabel=r"Diameter [$\mu$ m]",
    title="Scattering efficiency of a sphere",
)

image = ax.pcolormesh(permitivity, diameter, numpy.log(data))

plt.colorbar(mappable=image)

plt.show()