Frankfurt 2006 – wissenschaftliches Programm
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Q: Quantenoptik und Photonik
Q 72: Poster Laserspektroskopie
Q 72.1: Poster
Donnerstag, 16. März 2006, 16:30–18:30, Labsaal
Absorption and Emission Spectroscopic Characterization of some Vat, Direct, and Reactive Dyes — •Thomas Susdorf1, Alfons Penzkofer1, Sheng-Li Guo2, and Jing-Min Shi3 — 1Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetstrasse 31, D-93053 Regensburg, Germany — 2Department of Physics, Nanjing University of Information Science & Technology, Nanjing 210044, PR China — 3Department of Chemistry, Shandong Normal University, Jinan 250000, PR China
An optical spectroscopic characterization is carried out on a direct dye (acidproof purplish red), two reactive dyes (reactive orange 1 and reactive violet 8), two vat dyes (flavanthrone and flavanthrone-disodium-disulfite), and on N-(p-hydroxybenzylidene)-diamino-maleonitrile. The absorption cross-section spectra of the dyes are measured. A fluorescence spectroscopic characterisation is undertaken by measuring the fluorescence quantum distributions, fluorescence quantum yields, and the fluorescence lifetimes. The saturable absorption is studied by nonlinear transmission measurements with intense picosecond laser pulses (second harmonic pulses of a mode-locked Nd:glass laser). In the flavanthrone dyes and in reactive violet 8 impurity induced fluorescence quenching is observed. In acidproof purplish red, reactive orange 1, and the diamino-maleonitrile derivative there occurs fast ground-state recovery by internal conversion likely via conical intersections. Low excited-state absorption and fast ground-state absorption recovery make them ideal candidates for passive mode-locking of picosecond and femtosecond lasers as well as for fast nonlinear optical gating.