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 λ = 642 nm, nano-SILs are replicated on a transparent substrate by soft lithography. The focal spots produced by the nano-SILs show both spotsize reduction and peak-intensity enhancement, which are consistent with the immersion effect.