This book is an account of the physics of radiation and its interaction with matter in a particular spectral region. It is concerned with physical principles as they relate to far-infrared electromagnetic waves. In studying physics from such a point of view one naturally cuts across many of the usual boundaries of specialist research, but, in a field that has been beset by a sea of experimental difficulties, it is particularly desirable to be familiar with many, or most, aspects of the field. Thus we treat the processes of far-infrared wave generation, transmission and detection — always with an emphasis on basic principles—and the interaction of these waves with matter in its various forms: free electrons, semiconductors, plasmas, magnetic and nonmagnetic solids, etc.
It is the author's hope that the graduate student, the specialist research worker, and the scholar interested in physics seen in another rather special context will find interest in the following pages.