title: Imaging heterogeneous nanostructures with a plasmonic resonant ridge aperture.
abstract: We introduce a plasmonic resonance ridge aperture capable of sensing changes in refractive index and absorption with nanoscale resolution. Using this aperture, we devised a plasmonic near-field scanning nanoscope (PNSN) to record images of heterogeneous nanostructures. Compared to a conventional near-field scanning optical microscope (NSOM) that measures light scattered by the sample, the PNSN directly measures the change in a beam reflected from the aperture to detect buried objects. Using the PNSN we recorded images of nanoscale rectangular groove arrays on a SiO(2) substrate with patterns typical of a dynamic random access memory circuit. By comparing the experimental and calculated image of the nanostructure, we estimate the resolution of PNSN to be ~20 nm, which is ~50% smaller than the near-field spot generated by the aperture. Also, we theoretically analyzed the feasibility of the PNSN detecting an object underneath a metal film.
authors.affiliation: School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul, 120-749, Korea.
authors.forename: Taekyong
authors.initials: T
authors.lastname: Lee
authors.forename: Eungman
authors.initials: E
authors.lastname: Lee
authors.forename: Seonghyeon
authors.initials: S
authors.lastname: Oh
authors.forename: Jae W
authors.initials: JW
authors.lastname: Hahn