ABSTRACT
We care about optical properties of materials because they determine how materials look to human eyes. Light is an electromagnetic wave. Figure 8.1 shows the wavelengths of electromagnetic waves including visible light in air. The wavelength of visible light that humans can see ranges from 400 nm (violet light) to 700 nm (red light). The propagation of light through materials is controlled by the materials’ optical properties. For example, color in nature is a result of interactions between white light and materials. When white light enters matter, the electric and magnetic fields of light induce the electric and magnetic polarizations in materials. Since electromagnetic waves with different wavelengths interact differently with the induced dielectric and magnetic polarizations, only a part of the incident white light is reflected, scattered, refracted, absorbed, or transmitted. All types of these light-matter interactions contribute to the colors that we find in nature.
