Cylinder Scatterer Bohren-Huffman figure 8.8

/home/runner/work/PyMieSim/PyMieSim/docs/examples/validation/bohren_huffman/figure_88.py:97: UserWarning: Glyph 956 (\N{GREEK SMALL LETTER MU}) missing from font(s) cmr10.
  plt.tight_layout()

# Standard library imports
import numpy as np
import matplotlib.pyplot as plt
from TypedUnit import ureg

# PyMieSim imports
from PyMieSim.directories import validation_data_path
from PyMieSim.experiment.scatterer import Cylinder
from PyMieSim.experiment.source import Gaussian
from PyMieSim.experiment import Setup

# Load theoretical data
theoretical_data = np.genfromtxt(
    f"{validation_data_path}/bohren_huffman/figure_88.csv", delimiter=","
)

# Define parameters
wavelength = 632.8 * ureg.nanometer  # Wavelength of the source in meters
polarization_values = [0, 90] * ureg.degree  # Polarization values in degrees
optical_power = 1e-3 * ureg.watt  # Optical power in watts
NA = 0.2 * ureg.AU  # Numerical aperture
diameters = np.geomspace(10, 6000, 800) * ureg.nanometer  # Diameters from 10 nm to 6 μm
index = 1.55 * ureg.RIU  # Refractive index of the cylinder
medium_index = 1.335 * ureg.RIU  # Refractive index of the medium

# Calculate the volume of the cylinders
volumes = np.pi * (diameters / 2) ** 2

# Configure the Gaussian source
source = Gaussian(
    wavelength=wavelength,
    polarization=polarization_values,
    optical_power=optical_power,
    NA=NA,
)

# Setup cylindrical scatterers
scatterer = Cylinder(
    diameter=diameters, property=index, medium_property=medium_index, source=source
)

# Create experimental setup
experiment = Setup(scatterer=scatterer, source=source)

# Compute PyMieSim scattering cross section data
csca_data = (
    experiment.get("Csca", add_units=False)
    .squeeze()
    .values.reshape([-1, diameters.size])
)
normalized_csca = (
    csca_data / volumes.to_base_units() * 1e-4 / 100
)  # Normalize the data as per specific needs

# Plotting the results
plt.figure(figsize=(8, 4))
plt.plot(
    diameters * 1e6,
    normalized_csca[0],
    "C0-",
    linewidth=3,
    label="PyMieSim Polarization: 0",
)
plt.plot(
    diameters * 1e6,
    normalized_csca[1],
    "C1-",
    linewidth=3,
    label="PyMieSim Polarization: 90",
)
plt.plot(
    diameters * 1e6,
    theoretical_data[0],
    "k--",
    linewidth=1,
    label="Theoretical BH 8.8 Polarization: 0",
)
plt.plot(
    diameters * 1e6,
    theoretical_data[1],
    "k--",
    linewidth=1,
    label="Theoretical BH 8.8 Polarization: 90",
)

plt.xlabel("Diameter (μm)")
plt.ylabel("Normalized Scattering Cross Section")
plt.title("Comparison of Scattering Cross Sections for Cylinders")
plt.grid(True)
plt.legend()
plt.tight_layout()
plt.show()