Cylinder: Qsca vs Index

This example demonstrates how to compute and visualize the scattering efficiency (Qsca) as a function of refractive index for cylindrical scatterers using PyMieSim, considering multiple wavelengths.

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

Defining the source

source = Gaussian(
    wavelength=[500e-9, 1000e-9, 1500e-9],  # Array of wavelengths: 500 nm, 1000 nm, 1500 nm
    polarization_value=30,  # Polarization angle in degrees
    polarization_type='linear',
    optical_power=1e-3,  # 1 milliwatt
    NA=0.2  # Numerical Aperture
)

Defining the scatterer distribution

scatterer = Cylinder(
    diameter=800e-9,  # Fixed diameter of 800 nm
    index=np.linspace(1.3, 1.9, 1500),  # Refractive index ranging from 1.3 to 1.9
    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)

data = experiment.get(measure.Qsca)

Plotting the results Visualizing how the Qsca varies with the refractive index of the cylinder.

figure = data.plot(
    x=experiment.index,  # Refractive index as the x-axis
    y_scale='linear'  # Linear scale for the y-axis
)

Displaying the plot

_ = figure.show()

/home/docs/checkouts/readthedocs.org/user_builds/pymiesim/envs/master/lib/python3.11/site-packages/matplotlib/cbook.py:1699: ComplexWarning: Casting complex values to real discards the imaginary part
  return math.isfinite(val)
/home/docs/checkouts/readthedocs.org/user_builds/pymiesim/envs/master/lib/python3.11/site-packages/matplotlib/cbook.py:1345: ComplexWarning: Casting complex values to real discards the imaginary part
  return np.asarray(x, float)