Optical properties of the modern kinds of nano/microstructure materials - nuclear microfilters (NM) and their metallic replica (so called "needle structures" (NS)) are studied in visible as well as in IR region. The materials are produced from PolyEthylene Terephtalate (PET) film irradiated by accelerated Xe ions as well as by actinoids. The transparence of the ion-irradiated PET films decreases and the reflection increases with the duration of chemical treatment. The interference fringe pattern (IFP) becomes diffuse and weak at the final stages of the etching process. An intense diffraction background (DB) appears in the IR-spectra. A correlation between IFP and DB change and evoked by micropore formation the PET film mass losses is established. DB spectral form can be described by ~λ-2 law at initial stages of the etching and by standard Raleigh law (~λ-4) at
the end of the process. The optical properties of the NS prepared from copper and nickel on the base of the same NM are investigated. In both cases development of the surface roughness results in suppression of the "mirror-like" component in the reflected light. A phenomenon of the surface-enhanced IR scattering is discovered for Cu-NS. Possible applications of such nano/microstructure materials in optics are discussed.