Surface Plasmon Interference

A new nanophotolithography technique based on the interference of surface plasmon waves is proposed and demonstrated by using computer simulations. The wavelengths of the surface plasmon waves at metal and dielectric interfaces can reach the nanometer scale while their frequencies remain in the optical range. As a result, the resolution of this surface plasmon interference nanolithography (SPIN) can go far beyond the free-space diffraction limit of the light. Simulation results show that one-dimensional and two-dimensional periodical structures of 40−100 nm features can be patterned using interfering surface plasmons launched by 1D gratings. Detailed characteristics of SPIN such as field distribution and contrast are also investigated. As the most widely used form of lithography for almost all micromanufacturing purposes, photolithography was limited by the physics of diffraction. To achieve nano-meter feature sizes, either the working wavelength has to be reduced,1-3 or alternative techniques of pattern trans-fer such as nanoimprinting lithography (NIL)4,5 have to be adopted. The main approach to reducing the working wavelength is to directly use light sources of higher photo