Dynamics of small particles in electromagnetic radiation fields: A numerical solution

Abstract

We establish a theoretical framework for solving the equations of motion for an arbitrarily shaped, inhomogeneous dust particle in the presence of radiation pressure. The repeated scattering problem involved is solved using a state‐of‐the‐art volume integral equation‐based T‐matrix method. A Fortran implementation of the framework is used to solve the explicit time evolution of a homogeneous irregular sample geometry. The results are shown to be consistent with rigid body dynamics, between integrators, and comparable with predictions from an alignment efficiency potential map. Also, we demonstrate the explicit effect of single‐particle dynamics to observed polarization using the obtained orientational results.

Polarized scattering by Gaussian random particles under radiative torques

“…The software analyses the mesh geometry, then calculates the inertia parameters and the T -matrix of the scatterer. The T -matrix is determined by an implementation of the JVIE T -matrix method, abbreviated as T -VIE [25].…”

Optical Tweezers Exploring Neuroscience

“…This typically involves calculating the optical forces/torques that act on the particle and finding the equilibrium position/orientation. The most popular methods for calculating optical forces/torques in conventional OT are the T-matrix method (Nieminen et al, 2007;Herranen et al, 2017;Lenton, 2020a), geometric optics (Callegari et al, 2015), and for small weakly scattering particles, the dipole approximation or other zero-scattering approximations (Phillips et al, 2014). Recent advances have focused on combining these tools with dynamics simulations (Herranen et al, 2017;Lenton et al, 2018) and methods for calculating the non-optical forces such as the fluid dynamics or deformation of particles (Dao et al, 2003;Tapp et al, 2014).…”

Non-spherical particles in optical tweezers: A numerical solution

“…In this work, we use the full scattering solution of non-spherical particles of arbitrary composition to perform optical-tweezers modeling. In this section, we briefly review the foundational light-scattering framework, fully described by Herranen et al [7], and introduce the physical model of the optical tweezers system used in the calculations in the following.…”

“…The optical forces and torques are obtained from the total electric and magnetic fields, as the momentum-transferring interactions between light and the particle, described originally by Maxwell [22] and Poynting [23]. The momentum transfer can be solved analytically in the VSWF expansion, thus the forces and torques are essentially functions of the total fields [7,24,25]. Formally, this solution can be represented via force and torque efficiencies Q F and Q N , which are defined as…”

“…In previous studies [7,8] we have combined into a single software framework a T-matrix [9] scattering solution for particles of arbitrary shape and composition with an integrator of the equations of motion of the particle. This dynamical response by electromagnetic interactions is hereafter called scattering dynamics.…”