title: Femtosecond broadband fluorescence upconversion spectroscopy: Spectral coverage versus efficiency.
abstract: Sum frequency mixing of fluorescence and ∼1300 nm gate pulses, in a thin β-barium borate crystal and non-collinear type II geometry, is quantified as part of a femtosecond fluorimeter [X.-X. Zhang et al., Rev. Sci. Instrum. 82, 063108 (2011)]. For a series of fixed phasematching angles, the upconversion efficiency is measured depending on fluorescence wavelength. Two useful orientations of the crystal are related by rotation around the surface normal. Orientation A has higher efficiency (factor ∼3) compared to B at the cost of some loss of spectral coverage for a given crystal angle. It should be used when subtle changes of an otherwise stationary emission band are to be monitored. With orientation B, the fluorescence range λF > 420-750 nm is covered with a single setting of the crystal and less gate scatter around time zero. The accuracy of determining an instantaneous emission band shape is demonstrated by comparing results from two laboratories.
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, D-12489 Berlin, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Gerecke
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, D-12489 Berlin, Germany.
authors.forename: Genaro
authors.initials: G
authors.lastname: Bierhance
authors.affiliation: LIOP-TEC GmbH, Industriestrasse 4, D-42477 Radevormwald, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Gutmann
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-St. 2, D-12489 Berlin, Germany.
authors.forename: Nikolaus P
authors.initials: NP
authors.lastname: Ernsting
authors.affiliation: Départment de Chimie Physique, Université de Genève, 30, Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
authors.forename: Arnulf
authors.initials: A
authors.lastname: Rosspeintner