title: White-light nanosource with directional emission.
abstract: We report the first observation of white-light emission from femtosecond laser-induced plasma in a water droplet. Such emission is not observed with water in a cell. The microdroplet acts as a lens, focusing the incident light to nanosized regions within itself and directing the emission from these regions primarily back toward the laser source. This focusing increases the intensity so that multiphoton ionization generates plasma and causes it to reach the critical density during the initial part of the pulse, enabling the rest of the pulse to heat the plasma enough to emit in the visible.
authors.affiliation: Laboratoire de Spectrométrie Ionique et Moléculaire (UMR5579), Université Lyon 1, 69622 Villeurbanne Cedex, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Favre
authors.forename: Véronique
authors.initials: V
authors.lastname: Boutou
authors.forename: Steven C
authors.initials: SC
authors.lastname: Hill
authors.forename: Wiebke
authors.initials: W
authors.lastname: Zimmer
authors.forename: Marcel
authors.initials: M
authors.lastname: Krenz
authors.forename: Hendrik
authors.initials: H
authors.lastname: Lambrecht
authors.forename: Jin
authors.initials: J
authors.lastname: Yu
authors.forename: Richard K
authors.initials: RK
authors.lastname: Chang
authors.forename: Ludger
authors.initials: L
authors.lastname: Woeste
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Wolf