Figure 2
MPL array and plasmonic flying head enable high-throughput maskless plasmonic nanolithography (PNL) by focusing the ultraviolet laser energy into nano-scale spots onto the high speed spinning substrate.
(a) The SEM picture of a multistage plasmonic lens (MPL) consisting of a dumbbell-shaped aperture, a set of ring couplers (two inner rings) and a ring reflector (the outer ring), fabricated on a metallic thin film in 60 nm thick Cr film. The parameters of the centre aperture are shown in the insert, where W = 240 nm, H = 98 nm, R = 35 nm, r = 40 nm and d = 26 nm. The radii of the three rings are 240 nm 480 nm and 600 nm, respectively. And the width of the rings is 50 nm. (b) A SEM image of hexagonally packed MPL array. (c) The field intensity distribution at the plane 10 nm distance away from the MPL surface normalized to the incident intensity of 355 nm wavelength light. The half-circular shaped side lopes in the intensity profile are the direct transmissions through the three rings and their intensities are far below the exposure threshold of the resist. (d) A plasmonic flying head uses advanced airbearing surface (ABS) technology to maintain the gap between the lenses and the substrate at 10 nm at a linear scanning speed of 10 m/s.
