Thermodynamics of Surface Electromagnetic Waves (pp. 131-168)
Authors: (Illarion Dorofeyev, Institute for Physics of Microstructures, Russian Academy of Sciences, Nizhny, Novgorod, Russia)
Abstract: The chapter is devoted to the thermodynamics of normal surface electromagnetic fields within a nonuniform dispersive and absorptive system. This system is formed by vacuum and lossy medium separated by a plane interface. As a medium, we used dielectric and metal samples characterized by local and nonlocal optical properties. Thermodynamic properties of surface eigenmodes of plane interfaces are discussed. Various thermodynamic functions, different definitions of density of states and spectral characteristics of surface polaritons in equilibrium at the interface formed by vacuum and lossy medium are described and discussed. The generalized density of states is calculated based on the Barash-Ginzburg theory and dispersion relations for the surface states in different approaches. All formulas for thermodynamic functions are represented in terms of density of states. It is exemplified that different definitions of the density of states are identical in the case of dissipationless materials. The spectral functions and integrated over all frequencies thermodynamic characteristics and their temperature dependences are demonstrated.