The interaction of electromagnetic radiation with solid materials

Results are reported which were obtained during a theoretical program on the interaction of electromagnetic waves with solids. The report places special emphasis on the 1982 calendar year, which is the final year of the program. We have explored, during the tenure of the program a variety of interactions which influence the (linear) response of solids to external electromagnetic radiation, with emphasis on the frequency regime which extends from the visible, through the infrared and down to the microwave. Examples are the study of intrinsic free carrier scattering mechanisms in doped, polar materials, where our theory provides an excellent account of data with no adjustable parameters. Also, the scattering of electrons from phonons and other electrons in the near proximity of the surface, and their influence on the microwave response of metals has been explored. The last few years of the program saw increasing emphasis on the propagation of waves along interfaces with nonplanar profile (rough surfaces, periodic grating structures), and on the nonlinear interaction between waves in the near vicinity of planar, and nonplanar interfaces. In this body of work, perturbation theoretic methods were developed, which treat the deviations from a perfectly flat profile as small, and also we had considerable success with nonperturbative methods applied to periodic structures possibly of large amplitude.