Brownian dynamics simulations of optical blasting technique for manipulating colloidal crystal grain boundaries

We use Brownian Dynamics simulations to explore the new experimental ``optical blasting'' technique, in which a 1064 nm laser creates repulsive gradient forces on index-mismatched colloidal crystal particles. In the simulations, laser-induced forces are approximated using ray optics to calculate momentum transfer to the colloidal particles. Like our colloidal experiments, we find that the simulated optical blast forms small holes in 2-D colloidal crystals. When these holes form near grain boundaries (GB) the subsequent recovery of the crystal attracts the GB toward the location of the blast. By recreating this experimental setup \textit{in silico}, we systematically study how the effective attraction between the blast and the GB depends on the relative orientations of the crystal grains and the GB.