ABSTRACT
The subject of light–matter interaction is a vast area of physical science, covering a broad range of topics, from classical and quantum electrodynamics to the study of black holes and neutron stars. This chapter is concerned with the optical properties of nanomaterials and confined structures. More complex optical effects can occur for higher incident intensities, and typically can be observed when using higher power lasers. Such effects include second harmonic generation, where the incident frequency is doubled, and other nonlinear effects. The phenomena of refraction and absorption can be jointly described using the complex refractive index. The optical properties of insulating materials can be understood in much the same way, with similar physical mechanisms. Obviously, the difference being the size of the energy gap. Glasses form an important class of optical materials and have been known for many centuries, where their use in windows, glassware and optical instruments is well-known. More recent applications include optical fibers.
