Measuring colloidal forces from particle position deviations inside an optical trap
Abstract
We measure interaction forces between pairs of charged PMMA colloidal particles suspended in a relatively low-polar medium (5 ≲ ε ≲ 8) directly from the deviations of particle positions inside two time-shared optical traps. The particles are confined to optical point traps; one is held in a stationary trap and the other particle is brought closer in small steps while tracking the particle positions using