title: Subsurface nanoimaging by broadband terahertz pulse near-field microscopy.
abstract: Combined with terahertz (THz) time-domain spectroscopy, THz near-field microscopy based on an atomic force microscope is a technique that, while challenging to implement, is invaluable for probing low-energy light-matter interactions of solid-state and biomolecular nanostructures, which are usually embedded in background media. Here, we experimentally demonstrate a broadband THz pulse near-field microscope that provides subsurface nanoimaging of a metallic grating embedded in a dielectric film. The THz near-field microscope can obtain broadband nanoimaging of the subsurface grating with a nearly frequency-independent lateral resolution of 90 nm, corresponding to ∼ λ/3300, at 1 THz, while the AFM only provides a flat surface topography.
authors.affiliation: Department of Electrical and Computer Engineering, POSTECH , San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk 790-784, Korea.
authors.forename: Kiwon
authors.initials: K
authors.lastname: Moon
authors.forename: Hongkyu
authors.initials: H
authors.lastname: Park
authors.forename: Jeonghoi
authors.initials: J
authors.lastname: Kim
authors.forename: Youngwoong
authors.initials: Y
authors.lastname: Do
authors.forename: Soonsung
authors.initials: S
authors.lastname: Lee
authors.forename: Gyuseok
authors.initials: G
authors.lastname: Lee
authors.forename: Hyeona
authors.initials: H
authors.lastname: Kang
authors.forename: Haewook
authors.initials: H
authors.lastname: Han
keywords: Terahertz; nanospectroscopy; near-field microscopy; subsurface nanoimaging