The dispersion of surface plasmons at an air-metal interface has been studied experimentally using the method of attenuated total reflection. In the vicinity of the surface plasmon energy the dispersion curve was found to bend back toward the light line instead of increasing asymptotically to the surface plasmon energy at infinite momentum. We conclude that surface plasmon interactions must be characterized by a complete response-function surface rather than by a single dispersion curve.

Effect of Damping on Surface Plasmon Dispersion

The properties of polaritons which exist at the plane boundary between two isotropic dielectric media, one of which has a negative relative permittivity for part of the frequency range, are investigated by classical electromagnetic theory. The energy flow, density and velocity of the surface polariton are derived. The quantum-mechanical vector-potential operators in the two media are expressed in terms of surface-polariton creation and destruction operators. The thermal fluctuations in surface electric fields are determined, and the frequency-dependent relaxation rates of the surface polaritons are derived; the main concern is with polaritons which are mixtures of photons with optic phonons, but the photon-plasmon type of polariton is also discussed as a special case.

https://iopscience.iop.org/article/10.1088/0022-3719/7/19/015/pdf

Elementary properties of surface polaritons

The dispersion of ordinary and extraordinary phonon-like surface polaritons on α-quartz has been measured on two crystallographic faces parallel and perpendicular to the c-axis in the frequency range 350 to 1200 cm−1, covering all reststrahlen bands except the two lowest for polarization perpendicular to the optical axis The method used was the attenuated total reflection method for transverse magnetic polarized radiation The results are in very good agreement with theoretical calculations of the dispersion curves, using literature values for the freguencies of transverse and longitudinal optical phonons Cut-off wave vectors for so called “virtual excitation” surface polaritons are observed in agreement with theory



[Russian Text Ignored]

Dispersion of Phonon‐Like Surface Polaritons on α‐Quartz Observed by Attenuated Total Reflection

Lattice dynamics of crystal surfaces

Analysis of the physical properties of surfaces should be based on the maximum possible amount of information deduced from studies of the propagation of surface rather than volume electromagnetic waves, in which the energy is transported only along surfaces or separation boundaries between media. The present review, therefore, discusses a broad range of problems in the crystal optics of surface electromagnetic waves (surface polaritons), a subject developed in the course of the last few years. Various theoretical and experimental methods of investigating surface waves in crystals are discussed and compared, including a detailed review of Raman scattering of light. Other topics discussed include different effects in the spectra of surface waves due to the transition layer, the role of damping and spatial dispersion, the transformation of surface into volume waves, and so on. Possible fields of future research are suggested.

H. J. Queisser

Papers

Experimental studies of optical surface excitations

Dispersion of Surface Plasmons in InSb.