title: Extremely large extinction efficiency and field enhancement in terahertz resonant dipole nanoantennas.
abstract: The distinctive ability of nanometallic structures to manipulate light at the nanoscale has recently promoted their use for a spectacular set of applications in a wide range of areas of research including artificial optical materials, nano-imaging, biosensing, and nonlinear optics. Here we transfer this concept to the terahertz spectral region, demonstrating a metal nanostructure in shape of a dipole nanoantenna, which can efficiently resonate at terahertz frequencies, showing an effective cross section >100 times larger than its geometrical area, and a field enhancement factor of ~280, confined on a lateral section of ~λ/1,000. These results lead to immediate applications in terahertz artificial materials exhibiting giant dichroism, suggest the use of dipole nanoantennas in nanostructure-based terahertz metamaterials, and pave the way for nanoantenna-enhanced terahertz few-molecule spectroscopy and localized terahertz nonlinear optics.
authors.affiliation: Fondazione Istituto Italiano di Tecnologia, Genova, Italy. luca.razzari@iit.it
authors.forename: Luca
authors.initials: L
authors.lastname: Razzari
authors.forename: Andrea
authors.initials: A
authors.lastname: Toma
authors.forename: Mostafa
authors.initials: M
authors.lastname: Shalaby
authors.forename: Matteo
authors.initials: M
authors.lastname: Clerici
authors.forename: Remo Proietti
authors.initials: RP
authors.lastname: Zaccaria
authors.forename: Carlo
authors.initials: C
authors.lastname: Liberale
authors.forename: Sergio
authors.initials: S
authors.lastname: Marras
authors.forename: Ibraheem A I
authors.initials: IA
authors.lastname: Al-Naib
authors.forename: Gobind
authors.initials: G
authors.lastname: Das
authors.forename: Francesco
authors.initials: F
authors.lastname: De Angelis
authors.forename: Marco
authors.initials: M
authors.lastname: Peccianti
authors.forename: Andrea
authors.initials: A
authors.lastname: Falqui
authors.forename: Tsuneyuki
authors.initials: T
authors.lastname: Ozaki
authors.forename: Roberto
authors.initials: R
authors.lastname: Morandotti
authors.forename: Enzo
authors.initials: E
authors.lastname: Di Fabrizio
mesh_terms: D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D055053:Terahertz Radiation