OPTICAL-PROPERTIES OF COMPOSITE MEMBRANES CONTAINING ARRAYS OF NANOSCOPIC GOLD CYLINDERS

Arrays of nanoscopic Au cylinders were prepared by electrochemical deposition of Au within the pores of nanoporous (pore diameter = 50 nm) alumina template membranes. We show, for the first time, that the Au/alumina composite membranes obtained can be optically transparent into the visible portion of the electromagnetic spectrum. We also show that by changing the aspect ratio of the Au nanocylinders prepared, the color of the composite membrane can be reproducibly and predictably varied. Finally, we show that these results are in agreement with the predictions of Maxwell-Garnett theory for metal-insulator composites.