Reflow Of Non-Circular Nano-Pillars To Fabricate Nano-Scale Solid Immersion Lenses

We investigate the reflow of non-circular, i.e., triangular and square, shaped pillars to fabricate nano-scale solid immersion lenses (SILs). Electron beam lithography (EBL) and thermal reflow are the core of the fabrication process. For the optical characterization at lambda = 642 nm, nano-SILs are replicated on a transparent substrate by soft lithography. The focal spots produced by the nano-SILs show both spot-size reduction and peak-intensity enhancement, which are consistent with the immersion effect.