Attenuated total reflection angular spectra and associated resonant electromagnetic oscillations of a dielectric slab bounded by Ag films.

The attenuated total reflection (ATR) angular spectra of a layered system of Ag-MgF(2)-Ag, sandwiched between glass and air, have been measured at three different wavelengths in the visible region. Resonant electromagnetic (EM) oscillations are detected as narrow minima in the reflectance and sometimes as accompanying maxima in the transmittance of both p- and s-polarized light. Detailed calculations of the resonant EM fields illustrate the nature of the oscillations. Discrepancies between theory and experiment are thought to be due largely to the surface roughness of evaporated MgF(2) films. A cermet layer is imagined to form at the MgF(2)-Ag interface, and also an induced roughness layer at the Ag-air interface. When the optical constants of the cermet and roughness layers are evaluated by the Maxwell Garnett theory, the discrepancies for both polarizations can be accounted for in a consistent manner at all three wavelengths.