title: Squeezing millimeter waves through a single, nanometer-wide, centimeter-long slit.
abstract: We demonstrate broadband non-resonant squeezing of terahertz (THz) waves through an isolated 2-nm-wide, 2-cm-long slit (aspect ratio of 10(7)), representing a maximum intensity enhancement factor of one million. Unlike resonant nanogap structures, a single, effectively infinitely-long slit passes incident electromagnetic waves with no cutoff, enhances the electric field within the gap with a broad 1/f spectral response, and eliminates interference effects due to finite sample boundaries and adjacent elements. To construct such a uniform, isolated slit that is much longer than the millimeter-scale spot of a THz beam, we use atomic layer lithography to pattern vertical nanogaps in a metal film over an entire 4-inch wafer. We observe an increasing field enhancement as the slit width decreases from 20 nm to 2 nm, in agreement with numerical calculations.
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA.
authors.forename: Xiaoshu
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA.
authors.forename: Hyeong-Ryeol
authors.initials: HR
authors.lastname: Park
authors.affiliation: Physics Department, Bethel University, Saint Paul, MN 55112 USA.
authors.forename: Nathan C
authors.initials: NC
authors.lastname: Lindquist
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA.
authors.forename: Jonah
authors.initials: J
authors.lastname: Shaver
authors.affiliation: Department of Physics, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Pelton
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Oh