Photoacoustic determination of radiative quantum efficiency of surface plasmons in silver films

Abstract

Total light scattering from thin silver films in an attenuated-total-reflection geometry was determined as a function of the angle of incidence of 1.96-eV photons by using a combination of photoacoustic and optical measurements. From the results obtained at the plasmon resonance angle, the quantum efficiency of light emission from surface plasmons was determined as a function of film thickness and roughness. The thickness-dependent results, analyzed by the use of a Gaussian roughness spectrum, were found to be consistent with the predictions of Kröger and Kretschmann's theory for light scattering from rough thin films at all angles of incidence. From the values of the roughness parameters determined, the quantum efficiencies of light emission from the prism and the air sides of the silver film were evaluated as functions of film thickness.