Subwavelength lithography by waveguide mode interference

A subwavelength lithography method is demonstrated theoretically and experimentally through the interference of transverse electric (TE) modes in a metal-dielectric waveguide (MDW). Like surface plasmon polaritons (SPPs) on metal surfaces, the TE modes have evanescent waves leaking out of the MDW and are used to do subwavelength patterning but with larger pattern area than SPPs for their low propagation loss. The patterning resolution and depth could be optimized by modifying the thickness of the dielectric layer in the MDW. Two-dimensional subwavelength patterning using TE modes is also proposed with azimuthally polarized light exposure. (C) 2011 American Institute of Physics. [doi:10.1063/1.3651274]