Cylinder: Qabs vs Diameter

This example demonstrates how to compute and visualize the scattering efficiency (Qsca) as a function of diameter for cylindrical scatterers using PyMieSim.

Importing the package dependencies: numpy, PyMieSim

import numpy as np
from PyMieSim.experiment.scatterer import Cylinder
from PyMieSim.experiment.source import Gaussian
from PyMieSim.experiment import Setup
from PyMieSim import measure
from PyOptik import UsualMaterial

Defining the source

source = Gaussian(
    wavelength=400e-9,  # 400 nm
    polarization_value=0,  # Linear polarization angle in radians
    polarization_type='linear',
    optical_power=1e-3,  # 1 milliwatt
    NA=0.2  # Numerical Aperture
)

Defining the scatterer distribution

scatterer = Cylinder(
    diameter=np.linspace(1e-9, 800e-9, 300),  # Diameters ranging from 1 nm to 800 nm
    material=[UsualMaterial.Silver, UsualMaterial.Gold, UsualMaterial.Aluminium],  # Scatterer materials
    medium_index=1,  # Refractive index of the surrounding medium
    source=source
)

Setting up the experiment

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

Measuring the scattering efficiency (Qsca) Note: The original request mentioned Qsca, but the measurement code uses Qabs. If Qsca measurement is intended, ensure to use the correct measure object from PyMieSim.

data = experiment.get(measure.Qabs)  # Assuming Qabs was intended, replace with measure.Qsca if needed

Plotting the results Visualizing how the scattering efficiency varies with the cylinder diameter.

figure = data.plot(
    x=experiment.diameter,  # Cylinder diameter as the x-axis
    y_scale="linear"  # Linear scale for the y-axis
)

Displaying the plot

_ = figure.show()