Fluence-induced reversal of saturable absorption in a ruthenium-based porphyrin.
Appl Opt
; 56(3): B14-B17, 2017 Jan 20.
Article
em En
| MEDLINE
| ID: mdl-28157858
ABSTRACT
Experimental nonlinear absorption data obtained using the open-aperture Z-scan technique are presented for 2, 3, 7, 8, 12, 17, 18-octaethyl-21H, 23H-porphine ruthenium (II) carbonyl in tetrahydrofuran. These data show saturation of nonlinear absorption dominating at low fluence but being overcome by induced absorption (reverse saturable absorption) at high fluence. Large-angle scattering measurements demonstrate that the induced absorption is real and not merely the result of scattering of light outside of the collection aperture of the detector by scattering centers induced at high fluence. A possible mechanism based on a four-band effective rate equation model is proposed. The model is used to accurately predict the results of Z scans taken at different pulse energies and to extract values for excited-state lifetimes and absorption cross sections from the experimental data.
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Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article