Translation-rotation coupling in dense colloidal suspensions

Single-particle tracking has been used to contrast translational and rotational diffusion in colloidal suspensions. Not enough is known from prior study about the rotation of colloids, owing perhaps to the paucity of suitable measurements techniques, but this is now remedied by using Modulated Optical Nanoparticles(MOONs), which are fabricated by capping one hemisphere with a thin layer of reflective metal. Density of the suspensions is varied and both translational and rotational mean squared displacement are quantified.