Light is an electromagnetic wave. It consists of oscillating electric and magnetic fields that are perpendicular to each other. Since the constituents of matter (electrons and nuclei) can respond to the electric and magnetic fields, light can exert forces on small objects. The forces exerted by light on matter are called the radiation forces. Under suitable conditions, these radiation forces can be used to trap micron-sized objects, such as latex beads. The principle of localization of tiny objects in space using light is called "optical trapping" and it has found many applications in chemistry, physics and biology. This technique is most prominently used in biophysics to manipulate single biomolecules. The "optical trapping" is also used by atomic physicists to trap individual molecules and atoms.

In this experiment, we will learn how the radiation forces are used to trap tiny objects.