ABSTRACT
Optical forces arise from the conservation of momentum of light
scattered or absorbed by an object. If we assume any absorption
is minimal, and the object is made of a transparent dielectric with
a different refractive index from the surrounding medium, then the
scattering encompasses light refracting through, reflecting from and
diffracting around the particle. These interactions alter the direction
of the incident light, and hence change its momentum, therefore,
by Newton’s laws of motion, a resultant force is exerted on the
particle.