ABSTRACT
Light has played an important role in illuminating the life of human beings since ancient times. As its studies progressed, its nature and characteristics were revealed and understood. It has been found that light has three different characteristics from scientific point of view. The first one is the nature of light ray, known as geometrical optics. The second one is the nature of electromagnetic wave, known as wave optics. And the third one is the nature of photon, known as quantum optics. The uniqueness of light is that it includes these different natures in it. They are, however, the scientifically defined different aspects of one thing and related to each other in a very real sense. In this chapter, the first and second ones are included to introduce the basis of nanophotonics and surface plasmon resonance (SPR), which are keenly focused and studied recently. These technologies are expected to illuminate the darkness of the recent unsolved issues such as biological analysis, food and environmental safety, and energy source. 2.1 NanophotonicsLight is a kind of electromagnetic wave whose wavelength is from about 400 to about 700 nm. It consists of the oscillating electric field
and magnetic field, which are perpendicular to each other. Their relations can be expressed by Maxwell’s equations. — ¥ = - ∂∂
— ◊ =
E B t
E r e0
—¥ = ∂ ∂
+
—◊ =
B E t
J
B
m e m0 0 00where B is the magnetic field, E is the electric field, J is the electric current density, r is the electric charge density, m0 is the magnetic permeability, and e 0 is the dielectric permittivity. The technologies of light have astonishingly progressed since the laser (light amplification by stimulated emission) was innovated in 1960. The laser has provided the spatially coherent light and many applications are proposed and realized in 1980s. At present, light is used in many fields, as described below, and is necessary for our life and society. IlluminationsIllumination is the most traditional application of light from the ancient era. The tools for illumination have changed from fire to lamp, fluorescent light, LED (light-emitting diode), and organic electroluminescence. FabricationsLight is used to cut various materials. And its exposure is also used to fabricate very small patterns called lithography. Data Communications, Data StorageLight can carry digital information with it. And the data can be stored in optical disks and can be read by optical system. Material AnalysisThe constituent substances of a material can be analyzed by optical spectrum known as Raman, FT-IR (Fourier transform infrared), etc.
