A Simple Method for Producing Free-Standing, OpticallyDense Aluminium Foils with Randomly Distributed 100-nm Physical Through Holes for Biomedical Applications

摘要

Free-standing aluminium foils with 100-nm, randomly distributed through holes have been developed to study optical near-field phenomena on biomaterials. We used polycarbonate Isopore? membrane filters with 0.1-μm pores of perfect spherical cross-section as a substrate for an aluminium coating that later became the foil. The coated filter sheet was glued to a copper grid and the polycarbonate filter dissolved away. With a thickness of about 40 nm, the membranes blocked the light entirely aside from the light transmitted across the holes. The foils allow basic parameters of an envisaged optical near-field set-up to be investigated and optimized in a cost-effective, straightforward manner, using conventional far-field optics.