Nanofabrication with controllable localization energy based on the interference modulation of surface plasmons

A nanolithography technique based on the interference of surface plasmons (SPs) is proposed and demonstrated to modulate the localized exposure energy. The SP waves participating in interference are excited by two distinct structures, namely, the grating and the nanotaper. Constructive or destructive interference, which ultimately causes an enhanced or reduced modulation to the localized energy, can be obtained merely by adjusting the distance of the grating and the taper. Detailedly speaking, the localized energy can be modulated consecutively with a constant periodicity, and the modulation range of energy is extremely wide, for instance, the maximum energy is nearly 3 orders of magnitude larger than the minimum by our FDTD simulation results. Moreover, since the localized electric field at the taper tip, which leads to the exposure of the photoresist, is extremely sensitive to interference, it suggests a potential way to produce patterns with different depths and critical widths in one chip via beforehand programming and reasonably controlling the corresponding interference of SPs. (c) 2008 Optical Society of America.