title: Reaching the theoretical resonance quality factor limit in coaxial plasmonic nanoresonators fabricated by helium ion lithography.
abstract: Optical antenna structures have revolutionized the field of nano-optics by confining light to deep subwavelength dimensions for spectroscopy and sensing. In this work, we fabricated coaxial optical antennae with sub-10-nanometer critical dimensions using helium ion lithography (HIL). Wavelength dependent transmission measurements were used to determine the wavelength-dependent optical response. The quality factor of 11 achieved with our HIL fabricated structures matched the theoretically predicted quality factor for the idealized flawless gold resonators calculated by finite-difference time-domain (FDTD). For comparison, coaxial antennae with 30 nm critical dimensions were fabricated using both HIL and the more common Ga focus ion beam lithography (Ga-FIB). The quality factor of the Ga-FIB resonators was 60% of the ideal HIL results for the same design geometry due to limitations in the Ga-FIB fabrication process.
authors.affiliation: Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. mmelli@lbl.gov
authors.forename: M
authors.initials: M
authors.lastname: Melli
authors.forename: A
authors.initials: A
authors.lastname: Polyakov
authors.forename: D
authors.initials: D
authors.lastname: Gargas
authors.forename: C
authors.initials: C
authors.lastname: Huynh
authors.forename: L
authors.initials: L
authors.lastname: Scipioni
authors.forename: W
authors.initials: W
authors.lastname: Bao
authors.forename: D F
authors.initials: DF
authors.lastname: Ogletree
authors.forename: P J
authors.initials: PJ
authors.lastname: Schuck
authors.forename: S
authors.initials: S
authors.lastname: Cabrini
authors.forename: A
authors.initials: A
authors.lastname: Weber-Bargioni