Description

White light interacts with silver nanoparticles to produce bands of green and orange in the “ocean“– these scattering colors correspond to the nanoparticles’ plasmon resonance range. These silver nanoparticles are used to detect cancer cells.

Metal nanoparticles scatter light in a size-and-shape-dependent manner. When light of appropriate wavelength interacts with metal nanoparticles, the conduction electrons resonate (are excited) and their collective oscillation is called a surface plasmon. A drop of colloidal silver clusters is placed on a microscope slide under a confocal microscope and illuminated with white light. Near the ‘shore’ the thickness of the thin film of liquid shrinks causing a repeating set of interference fringes of color spanning the rainbow. Yet, since the silver plasmon resonance scatters the green and orange colors better than blue and red, the visual effect is a convolution from the wave nature of light (interference) with the complex plasmonic resonance of silver clusters.