With the use of light, traditional microscopes enhance images of minute structures or objects. On the other hand, Nanoparticles are so small that they rarely absorb or scatter light and go undetected. An optical resonator boosts light-nanoparticle interaction by capturing light in the smallest possible space by reflecting it thousands of times between two mirrors.
If a nanoparticle is present in the captured light field, it interacts with the light thousands of times, allowing the change in light intensity to be detected (optical resonator). At different points in space, the light field has varied intensities. The variation in intensity provides information about the nanoparticle’s position in three-dimensional space.
When a nanoparticle lands in the water, it collides with water molecules moving in random directions due to thermal energy. The nanoparticles move at random as a result of these collisions. It is now possible to recognize the Brownian motion.