title: Photonic jet driven non-linear optics: example of two-photon fluorescence enhancement by dielectric microspheres.
abstract: The two-photon excited fluorescence from a dye solution is enhanced when a small amount of micro-meter sized silica beads are added. This observation is made in the simple scattering regime (inter-sphere distance four times larger than their radius) and is shown to depend on the concentration of the silica spheres. For a solution of rhodamine B, the enhancement can reach more than 30 %. As complementary experiments show that the fluorescence efficiency is unchanged, we argue that the non-linear absorption is enhanced due to focussing of the incident beam in the near-field of the spheres, a situation previously referred to as photonic (nano-)jets [3]. Our calculations indeed show that for the parameters of the spheres studied near-field focussing leads to an intensity concentration close to the sphere surface. We suggest that these photonic jets could be used to enhance other non-linear optical effects.
authors.affiliation: Optical Communication Systems Laboratory, School of Electrical Engineering and Computer Sciences, Seoul National University, Seoul 151-744, South Korea
authors.forename: Sylvain
authors.initials: S
authors.lastname: Lecler
authors.forename: Stefan
authors.initials: S
authors.lastname: Haacke
authors.forename: Nhan
authors.initials: N
authors.lastname: Lecong
authors.forename: Olivier
authors.initials: O
authors.lastname: Crégut
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Rehspringer
authors.forename: Charles
authors.initials: C
authors.lastname: Hirlimann