Optical properties of microporous polymer membranes coated with metal have been studied using scanning near-field 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.
- Near-field optical microscopy
- Optics of microstructured thin films
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering