title: Observation of strongly enhanced ultrashort pulses in 3-D metallic funnel-waveguide.
abstract: For strong field enhancement of ultrashort light pulses, a 3-D metallic funnel-waveguide is analyzed using the finite-difference time-domain (FDTD) method. Then the maximum intensity enhancement actually developed by the funnel-waveguide upon the injection of femtosecond laser pulses is observed using two-photon luminescence (TPL) microscopy. In addition, the ultrafast dephasing profile of the localized field at the hot spot of the funnel-waveguide is verified through the interferometric autocorrelation of the TPL signal. Finally it is concluded the funnel-waveguide is an effective 3-D nanostructure that is capable of boosting the peak pulse intensity of stronger than 80 TWcm(-2) by an enhancement factor of 20 dB without significant degradation of the ultrafast spatiotemporal characteristics of the original pulses.
authors.forename: Dong-Hyub
authors.initials: DH
authors.lastname: Lee
authors.forename: Joonhee
authors.initials: J
authors.lastname: Choi
authors.forename: Seungchul
authors.initials: S
authors.lastname: Kim
authors.forename: In-Yong
authors.initials: IY
authors.lastname: Park
authors.forename: Seunghwoi
authors.initials: S
authors.lastname: Han
authors.forename: Hyunwoong
authors.initials: H
authors.lastname: Kim
authors.forename: Seung-Woo
authors.initials: SW
authors.lastname: Kim