Analysis of Field and Force Calculation of Multiple Rayleigh Scattering

Rayleigh approximation is one of the basic methods of studying electromagnetic (EM) scattering of light for spherical particle. We consider a large sphere consisting of many small Rayleigh particles, and then calculate the electric and magnetic fields of that large sphere. We simulate the field patterns of electric and magnetic field of a large sphere using discrete dipole approximation (DDA) method and compare the field patterns with Mie theory. We calculate the total numerical force acting on the sphere considering scattering and gradient force and calculate the same force using Chu stress tensor and Mie theory. We also figure out the force distribution inside the sphere using DDA method and compare it with force density using Mie theory and Chu force tensor. We observe the force distribution inside the sphere by changing the lattice formation using cubic and triangle lattice formation.