Fabrication of arrays of sub-wavelength nano-apertures in an optically thick gold layer onglass slides for optical studies

Abstract

We report on the fabrication of two-dimensional arrays of nano-optical apertures ingold layers by electron beam lithography (EBL) on a transparent glass substrate.30 × 30 µm2 large arrays of high aspect ratio sub-wavelength cylinders (400 nm diameter with period of1.81 µm) and annular apertures (diameters 250/330 nm and 310/330 nm inner/outer with period of600 nm) were patterned in a 750 nm thick resist layer using a high contrast negative toneresist. The resist structures show sharp and vertical edges after development.The 150 nm thick deposited gold layer ensures optical transmission of less than1.1 × 10−4 at 633 nm wavelength. White light based optical characterizations agreed with theorypredictions and prove the good quality of the structures.