Share Email Print

Proceedings Paper

Combined optical gain and degradation measurements in DCM2 doped Tris-(8-hydroxyquinoline)aluminum thin-films
Author(s): Marko Čehovski; Sebastian Döring; Torsten Rabe; Reinhard Caspary; Wolfgang Kowalsky
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

Organic laser sources offer the opportunity to integrate flexible and widely tunable lasers in polymer waveguide circuits, e.g. for Lab-on-Foil applications. Therefore, it is necessary to understand gain and degradation processes for long-term operation. In this paper we address the challenge of life-time (degradation) measurements of photoluminescence (PL) and optical gain in thin-film lasers. The well known guest-host system of aluminum-chelate Alq3 (Tris-(8-hydroxyquinoline)aluminum) as host material and the laser dye DCM2 (4-(Dicyanomethylene)-2- methyl-6-julolidyl-9-enyl-4H-pyran) as guest material is employed as laser active material. Sample layers have been built up by co-evaporation in an ultrahigh (UHV) vacuum chamber. 200nm thick films of Alq3:DCM2 with different doping concentrations have been processed onto glass and thermally oxidized silicon substrates. The gain measurements have been performed by the variable stripe length (VSL) method. This measurement technique allows to determine the thin-film waveguide gain and loss, respectively. For the measurements the samples were excited with UV irradiation (ƛ = 355nm) under nitrogen atmosphere by a passively Q-switched laser source. PL degradation measurements with regard to the optical gain have been done at laser threshold (approximately 3 μJ/cm2), five times above laser threshold and 10 times above laser threshold. A t50-PL lifetime of > 107 pulses could be measured at a maximum excitation energy density of 32 μJ/cm2. This allows for a detailed analysis of the gain degradation mechanism and therefore of the stimulated cross section. Depending on the DCM2 doping concentration C the stimulated cross section was reduced by 35 %. Nevertheless, the results emphasizes the necessity of the investigation of degradation processes in organic laser sources for long-term applications.

Paper Details

Date Published: 27 April 2016
PDF: 7 pages
Proc. SPIE 9895, Organic Photonics VII, 989508 (27 April 2016); doi: 10.1117/12.2227688
Show Author Affiliations
Marko Čehovski, Technische Univ. Braunschweig (Germany)
Sebastian Döring, Technische Univ. Braunschweig (Germany)
Torsten Rabe, Technische Univ. Braunschweig (Germany)
Reinhard Caspary, Technische Univ. Braunschweig (Germany)
Wolfgang Kowalsky, Technische Univ. Braunschweig (Germany)

Published in SPIE Proceedings Vol. 9895:
Organic Photonics VII
David Cheyns; Pierre M. Beaujuge; Volker van Elsbergen; Jean-Charles Ribierre, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?