Near-field optical microscopy of strongly scattering microporous metal/polymer membranes

Author :G.T. Shubeita, S.K. Sekatskii, G. Dietler, S. Takahashi, A.V. Zayats
Publication :Optics Communications
Volume :217
Pages :23-30
Year :2003

Optical properties of microporous polymer membranes coated with metal have been studied using scanning nearfield
optical microscopy. The electromagnetic field distribution close to pores of various sizes ranging from 35 to 750 nm
has been investigated in the different illumination configurations. Individual pores as small as 35 nm were seen in the
near field. For directly illuminated membranes the field distribution is related mainly to the pores themselves. However,
when surface plasmon polaritons were excited, the field distribution exhibited much more complex structure related to
the interaction of surface polaritons with the ensemble of randomly distributed pores and metal surface roughness as
well as localized surface plasmon effects. The results will be of importance for the understanding of optical properties of
subwavelength apertures in strongly scattering films as well as optics of randomly structured metal films.