Fluorescence behaviour of highly concentrated rhodamine 6G solutions

Penzkofer, Alfons; Leupacher, W.

doi:10.1016/0022-2313(87)90167-0

Cited by 245 publications

(145 citation statements)

References 27 publications

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“…The fluorescence spectra are measured using front-face illumination in a self-assembled spectrofluorimeter [7]. A spectrally filtered tungsten lamp is used as excitation source.…”

Section: Methodsmentioning

confidence: 99%

“…The determination of the fluorescence quantum distribution, E(X) (nm -1 ), and of the fluorescence quantum efficiency, q ¥ = f em E(X) d\, from the measured fluorescence signal is described in ref. [7]. E(X) is defined as the ratio of the intrinsically generated fluorescence photons per nm wavelength interval at wavelength X to the absorbed pump light photons.…”

Section: Methodsmentioning

confidence: 99%

“…At high concentrations (result of C = 0.08 mol/dm 3 ) the fluorescence signal is completely depolarized (r F = 0). The fast Förster-type energy transfer between excited and unexcited molecules (k E > r F *) at high concentration [11,12,7] depolarizes the fluorescence emission (r F -> 0, independent of solvent viscosity). cm, P = X^1].…”

Section: E(\mentioning

confidence: 99%

“…The ratio of the absorption cross sections of the vibronic shoulder to the absorption peak is increased in the closely spaced pairs [a A?D (510 nm)/a AD (542 nm) = 0.48; a AM (508 nm)/a AJVI (540 nm) = 0.28]. The enlarged absorption of the vibronic shoulder compared to the absorption peak indicates a slightly larger Franck-Condon shift (difference in equilibrium position between S x state and S 0 state) of the closely spaced pairs compared to the monomers [7,10,[25][26][27].…”

Section: E(\mentioning

confidence: 99%

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Concentration-dependent absorption and emission behaviour of a pyrimidonecarbocyanine dye in hexafluoroisopropanol

et al. 1987

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“…The fluorescence spectra are measured using front-face illumination in a self-assembled spectrofluorimeter [7]. A spectrally filtered tungsten lamp is used as excitation source.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: E(\mentioning

confidence: 99%

Section: E(\mentioning

confidence: 99%

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Concentration-dependent absorption and emission behaviour of a pyrimidonecarbocyanine dye in hexafluoroisopropanol

et al. 1987

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“…The fluorescence quantum yield measurement system is described in ref. [16].Kiton Red 620 has been previously used in hybrid mode-locked systems pumped by the second harmonic of a mode-locked Nd: YAG laser, and pulses as short as 29 fs were obtained at 615 nm when a mixture of DODCI and DQOCI was used as saturable absorber in a dispersion optimized linear cavity …”

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confidence: 99%

Femtosecond pulse generation around 650 nm in a passive mode-locked Kiton Red dye laser

Petrov

Wittmann

Bäumler

et al. 1993

Optics Communications

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Sub 100 fs light pulses have been generated in the spectral region between 640 and 660 nm (the shortest duration being 50 fs at 653 nm) by passive mode-locking of a Kiton Red dye laser with the saturable absorber DQTCI.Nearly the whole visible and near infrared range (with some gaps) has been covered by various amplifying dye-saturable absorber combinations yielding femtosecond light pulses in cw passive or hybrid mode locked lasers [1][2][3][4]. Pulse durations below 150 fs were obtained in some of these combinations by group velocity dispersion balanced laser operation [5].In the spectral region around 650 nm sub 100 fs pulse generation has not been reported so far. The longest wavelength achieved by passive mode-locking of a Rhodamine 6G laser was 640 nm [ 6 ]. In this laser 50 fs pulses at 640 nm have been generated by the saturable absorber TCETI. Energy transfer passive mode-locking with an argon ion pump laser has been applied to cover the 652-694 nm region with Rhodamine 6G+Sulforhodamine 101 mixtures as gain medium and DQTCI or DCCI as saturable absorbers [ 7,8 ]. The shortest pulse durations obtained were 58 fs at 685 nm [8] and 120 fs at 666 nm [7]. Applying hybridly mode-locked systems pumped by the second harmonic of Nd:YAG lasers [9,10], pulses of 65 fs duration at 640 nm [9] have been obtained in a Rhodamine 6G/DODCI laser, and pulses of 60 fs duration at 675 nm were generated using Rhodamine 101 or Sulforhodamine 101 as gain media and DQTCI as absorber medium [10]. Subpicosecond Rhodamine B lasers have been operated 1 On leave from the Faculty of Physics, Sofia University, BG-1126 Sofia, Bulgaria.around 650 nm [10][11][12]. Cw passive mode-locking with DQTCI was achieved in the wavelength region of 616-658 nm [11]. However, the shortest duration was 220 fs at 635 nm [11]. Hybrid mode-locking of Rhodamin B lasers resulted in pulses of duration down to 320 fs in the spectral region between 604 and 632 nm when DQTCI or DDBCI were used as saturable absorbers [10,12]. Using Oxazine 720 as saturable absorber pulse durations down to 187 fs were obtained around 649 nm [10].Here we report on passive mode-locking of a Kiton Red laser with the saturable absorber DQTCI [13] producing sub 100 fs pulses in the wavelength region of 640-660 nm. The dyes Kiton Red 620 (Sulforhodamine B, free of sodium) [13,14] and DQTCI (1,3' -diethyl-4,2' -quinolythiacarbocyanine iodide) [13,15] were purchased from Lambda Physik. The fluorescence quantum yield of Kiton Red 620 in ethylene glycol was determined to be

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Laser action in poly (m‐phenylenevinylene‐co‐2,5‐dioctoxy‐p‐phenylenevinylene)

et al. 1996

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Communications presence of these levels is likely to be responsible for the filling of the "valley" near 9 eV in the spectrum of PPV.In conclusion, it has been shown that exposure of PPV films to air and in the dark lead to inclusion of water molecules in three different types of site. In particular, the formation of complex, C-like structures leads to increases in torsion angles in such a way as to reduce the conjugation and increase the HOMO-LUMO band gap. The effects of the geometrical changes, and the associated electronic structural changes, are clearly seen in the UPS measurements. Effects seen in the optical absorption spectra are consistent with the occurrence of water-induced changes in the frontier electronic structure, but appear to be more complicated than the UPS data and the modelling might suggest. The effects reported are completely reversible, disappearing upon heat treatment of PPV in UHV. A recipe for preparing clean PPV films is proposed. ExperimentalThe PPV samples were prepared from a soluble THT-leaving group precursor polymer [14] obtained from Cambridge Display Technology, Cambridge. UK. Thin films of thickness about 10,20, or 30 nm were spin-coated onto optically flat Si(ll0) wafers, and converted at 240°C for 10 h under a mild vacuum of 5 x mbar. Samples were then sealed in dry nitrogen gas for shipment to Linkoping. For subsequent studies, "as-prepared", "clean" films were made by heating each sample at 150 "C overnight in a vacuum of better than 10. ' mbar, prior to measurements, as discussed previously [9]. A complete set of XPS and UPS valence band spectra were recorded, establishing the quality of the films. In the XPS data, the residual oxygen was found to be

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Fluorescence behaviour of highly concentrated rhodamine 6G solutions

Cited by 245 publications

References 27 publications

Concentration-dependent absorption and emission behaviour of a pyrimidonecarbocyanine dye in hexafluoroisopropanol

Concentration-dependent absorption and emission behaviour of a pyrimidonecarbocyanine dye in hexafluoroisopropanol

Femtosecond pulse generation around 650 nm in a passive mode-locked Kiton Red dye laser

Laser action in poly (m‐phenylenevinylene‐co‐2,5‐dioctoxy‐p‐phenylenevinylene)

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