Surface plasmon-polariton study of the optical dielectric function of zinc

The optical dielectric function of zinc is measured by excitation of surfac e plasmon-polaritons on a silica prism coated in MgF2 and zinc in the Kretc hmann configuration and on a zinc-covered silica grating for a range of wav elengths in the Visible spectrum. By exciting the surface plasmon at the zi nc-MgF2 or zinc-grating interfaces, the zinc is protected from oxidization and contamination. Comparison of angle-dependent reflectivities with either Fresnel's theory or grating modelling theory gives both the real and imagi nary parts of the dielectric function of the zinc over the visible spectrum . The results compare very favourably with those obtained by other workers using more conventional methods for samples held in vacuum.