title: Optical fiber tip for field-enhanced second harmonic generation.
abstract: We propose a simple optical fiber tip for field-enhanced second harmonic generation (SHG). The tip shows nonlinear phenomena of SHG over a wide range of sources, at least from 630 to 830 nm. The optical field corresponding to the second harmonic appears as a nondiffracting bottle beam with voids due to the surface curvature of the tip. The field-enhanced second harmonic can also induce surface plasmons, converting the tip to a plasmonic probe with reduced background signal. The tip can be useful in nanophotonics characterization. As an example, we demonstrate the tip's response as a surface-enhanced Raman spectroscopy probe.
authors.affiliation: CSIR-Central Scientific Instruments Organisation, Sector 30C, Chandigarh 160030, India.
authors.forename: Sudipta Sarkar
authors.initials: SS
authors.lastname: Pal
authors.forename: Samir K
authors.initials: SK
authors.lastname: Mondal
authors.forename: Phun Phun
authors.initials: PP
authors.lastname: Bajpai
authors.forename: Pawan
authors.initials: P
authors.lastname: Kapur