ABSTRACT
Metal nanoparticles are now being exploited extensively in materials science, optics, chemistry, biology, and medicine because they interact strongly with visible and infrared light. ey have proven to be excellent optical nanoantennas, acting as robust radiation receivers, localizers, and emitters that can connect light to the nanoworld. e optical properties of metallic nanoparticles are governed mainly by the excitation of electromagnetic surface modes, so-called surface plasmons. ese modes are maintained by resonant oscillations of the surface charge density at the boundaries of the metal nanoparticle (see Figure 24.1). For simple metal nanoparticles, such as nanospheres or nanorods, the basic plasmon mode is a dipole charge oscillation, as shown in Figure 24.1, just as it would be in a traditional radio wave antenna.
