Generalized Kubelka-Munk approximation for multiple scattering of polarized light

Area of Science:

• Optics
• Electromagnetism
• Computational Physics

Background:

• Multiple scattering of polarized light is crucial in understanding light interaction with matter.
• Existing models often struggle to accurately capture polarization effects in complex scattering scenarios.
• The vector radiative transfer equation (vRTE) provides a comprehensive description but is computationally intensive.

Purpose of the Study:

• To introduce a computationally efficient approximation for modeling polarized light multiple scattering.
• To validate the accuracy of the generalized Kubelka-Munk (gKM) approximation against the vRTE.
• To assess the gKM approximation's ability to capture polarization characteristics of backscattered light.

Main Methods:

• Developed the generalized Kubelka-Munk (gKM) approximation via linear transformation of the double spherical harmonics approximation (order one) of the vRTE.
• Formulated a simplified 32x32 system of differential equations.
• Compared numerical solutions of the gKM approximation with the vRTE for light incident on a plane-parallel slab.

Main Results:

• The gKM approximation provides a significantly simpler system of equations compared to the vRTE.
• Numerical comparisons demonstrate that the gKM approximation accurately reproduces key features of the polarization state of multiply scattered light.
• The gKM approximation shows high accuracy in capturing complex polarization characteristics of backscattered light from dielectric spheres in optically thick media.

Conclusions:

• The generalized Kubelka-Munk (gKM) approximation is a viable and accurate alternative to the vRTE for modeling polarized light multiple scattering.
• This new model simplifies complex radiative transfer problems, offering computational advantages.
• The gKM approximation's success in predicting polarization phenomena highlights its potential for applications in diverse fields involving light scattering.