title: Controlling terahertz radiation with nanoscale metal barriers embedded in nano slot antennas.
abstract: Nanoscale metallic barriers embedded in terahertz (THz) slot antennas are shown to provide unprecedented control of the transition state arising at the crossover between the full- and half-wavelength resonant modes of such antennas. We demonstrate strong near-field coupling between two paired THz slot antennas separated by a 5 nm wide nanobarrier, almost fully inducing the shift to the resonance of the double-length slot antenna. This increases by a factor of 50 the length-scale needed to observe similar coupling strengths in conventional air-gap antennas (around 0.1 nm), making the transition state readily accessible to experiment. Our measurements are in good agreement with a quantitative theoretical modeling, which also provides a simple physical picture of our observations.
authors.affiliation: Center for Subwavelength Optics, Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
authors.forename: Hyeong-Ryeol
authors.initials: HR
authors.lastname: Park
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Bahk
authors.forename: Kwang Jun
authors.initials: KJ
authors.lastname: Ahn
authors.forename: Q-Han
authors.initials: QH
authors.lastname: Park
authors.forename: Dai-Sik
authors.initials: DS
authors.lastname: Kim
authors.forename: Luis
authors.initials: L
authors.lastname: Martín-Moreno
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: García-Vidal
authors.forename: Jorge
authors.initials: J
authors.lastname: Bravo-Abad