CoreShell: Coupling vs Diameter

This example demonstrates how to compute and visualize the coupling efficiency as a function of core diameter for CoreShell scatterers using PyMieSim.

Importing the package dependencies: numpy, PyMieSim

import numpy
from PyMieSim.experiment.detector import Photodiode
from PyMieSim.experiment.scatterer import CoreShell
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=1.2e-6,  # 1200 nm
    polarization_value=90,  # Polarization angle in degrees
    polarization_type='linear',
    optical_power=1e-3,  # 1 milliwatt
    NA=0.2  # Numerical Aperture
)

Defining the scatterer distribution

scatterer = CoreShell(
    core_diameter=numpy.geomspace(100e-9, 600e-9, 400),  # Core diameters from 100 nm to 600 nm
    shell_width=800e-9,  # Shell width of 800 nm
    core_material=UsualMaterial.Silver,  # Core material
    shell_material=UsualMaterial.BK7,  # Shell material
    medium_index=1,  # Surrounding medium's refractive index
    source=source
)

Defining the detector

detector = Photodiode(
    NA=[0.1, 0.05],  # Numerical Apertures for the detector
    phi_offset=-180.0,  # Phi offset in degrees
    gamma_offset=0.0,  # Gamma offset in degrees
    sampling=600,  # Number of sampling points
    polarization_filter=None  # No polarization filter
)

Setting up the experiment

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

Measuring the coupling efficiency

data = experiment.get(measure.coupling)

Plotting the results Visualizing how the coupling efficiency varies with the core diameter.

figure = data.plot(
    x=experiment.core_diameter,  # Core diameter as the x-axis
    y_scale='linear',  # Linear scale for the y-axis
    normalize=True,  # Normalizing the results
)

Displaying the plot

_ = figure.show()