Photonic Properties of Butterfly Wing Infiltrated with Ag-Nanoparticles

We report on the establishment of photonic band gap in naturally available white Indian butterfly wing (Pieris Brassicae) by growing Ag nanoparticles through surface adsorption onto its periodically arrayed fiber stems and air-gaps. The first reflectance peak maximum due to chitin layer was observable at similar to 265 nm. The gradual evolution of other reflectance peak maxima (similar to 335-355 nm; similar to 680-730 nm) with increasing reaction time is ascribed to the effective surface adsorption mediated by insertion and conversion of Ag+ to Ag-0 through the chitin layers of the wings and excitation of localized surface plasmon (LSP) around the homogeneously distributed air-holes. Polarized reflectance spectroscopy of specimen processed for 8 h has revealed stronger participation of surface plasmons along P-polarization direction compared to S-polarization. The structurally obtained patterns, as a result of physicochemical processing were characterized by electron microscopy and reflectance spectroscopy tools. Such naturally available biological templates decorated with nanoscale metals would find scope for interfacing elements related to nanophotonics and plasmonics.