title: Resonant Effects in Nanoscale Bowtie Apertures.
abstract: Nanoscale bowtie aperture antennas can be used to focus light well below the diffraction limit with extremely high transmission efficiencies. This paper studies the spectral dependence of the transmission through nanoscale bowtie apertures defined in a silver film. A realistic bowtie aperture is numerically modeled using the Finite Difference Time Domain (FDTD) method. Results show that the transmission spectrum is dominated by Fabry-Pérot (F-P) waveguide modes and plasmonic modes. The F-P resonance is sensitive to the thickness of the film and the plasmonic resonant mode is closely related to the gap distance of the bowtie aperture. Both characteristics significantly affect the transmission spectrum. To verify these numerical results, bowtie apertures are FIB milled in a silver film. Experimental transmission measurements agree with simulation data. Based on this result, nanoscale bowtie apertures can be optimized to realize deep sub-wavelength confinement with high transmission efficiency with applications to nanolithography, data storage, and bio-chemical sensing.
authors.affiliation: Department of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ding
authors.affiliation: Department of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Qin
authors.affiliation: Department of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Songpo
authors.initials: S
authors.lastname: Guo
authors.affiliation: Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Kinzel
authors.affiliation: Department of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang