Transient transmission

Figure 10-5. Transient transmission changes AV/Po in PPV for different lime delays between the pump and probe pulse. The pump pulse is a 100 fs laser pulse at 325 nm obtained by frequency doubling ol amplified dye laser pulses, (a) and (b) correspond to different sides of a PPV-film. The spectra in (a) were obtained lor the unoxidized side of the sample while the set of spectra in (b) was measured for the oxidized side of the same sample. The main differences observed are a much lower stimulated emission effect for the oxidized side. The two bottom spectra depict the PL-spectra for comparison. The dashed line indicates the optical absorption (according to Kef. (281).

Figure 3.6 Near-field transient transmission image of a single gold nanorod observed at 0.6 ps (a) and corresponding simulated image (b). (Reproduced with permission from The American Physical Society [27]).

Fig. 2.16. G-mode frequency of SWNTs as a function of pump-probe time delay obtained from transient transmission measurement using a sub-10 fe pulse at 2.1 eV. From [55]...

Fig. 1. Transient transmission at different excitation and probe wavelengths. Insets show the Fourier transformations of the oscillatory contributions at 630 nm for different excitation wavelengths.

Fig. 4. Comparison of the transient transmission of BP(OH)2 (triangles) and BP(OD)2 (circles) excited at 350 nm and probed at 505 nm. No differences in the delay of the emission rise and the oscillation pattern are observed.

Fig. 10.28 a) Stationary absorption spectrum of the N3 Ru dye (dotted curve), of the oxidized N3 dye (dashed curve), both in absolute ethanol, and the difference of these curves (solid curve), b) Transient transmission signal due to N3 dye molecules anchored to the colloidal Ti02 electrode in ultrahigh vacuum. The parameter is the time delay between pump puLse and probe pulse.s. (The results were nearly the same for electrodes immersed in the solution.) The absorption spectrum of the excited triplet state of the N3 dye, measured in ethanol, is shown for comparison (solid squares). (After ref. [51])... 

An electronic or vibrational excited state has a finite global lifetime and its de-excitation, when it is not metastable, is very fast compared to the standard measurement time conditions. Dedicated lifetime measurements are a part of spectroscopy known as time domain spectroscopy. One of the methods is based on the existence of pulsed lasers that can deliver radiation beams of very short duration and adjustable repetition rates. The frequency of the radiation pulse of these lasers, tuned to the frequency of a discrete transition, as in a free-electron laser (FEL), can be used to determine the lifetime of the excited state of the transition in a pump-probe experiment. In this method, a pump energy pulse produces a transient transmission dip of the sample at the transition frequency due to saturation. The evolution of this dip with time is probed by a low-intensity pulse at the same frequency, as a function of the delay between the pump and probe pulses.1 When the decay is exponential, the slope of the decay of the transmission dip as a function of the delay, plotted in a log-linear scale, provides a value of the lifetime of the excited state. 

Fig. 4.12 Transient transmission signal traces obtained in the gold nanorod (diameter 30 nm, length 300 nm). Solid curves indicate double (for a, c-e) and single (for b) exponential fits. Inset observed positions in the nanorod...

Fig. 4.13 (a) Near-field transient transmission image of the nanorod taken at delay time of 600 fs. (b) Simulated transient transmission image of the nanorod. Dotted lines approximate shape of the nanorod. Scale bars 100 nm... 

Figure 10.28 (a) Stationary absorption spectrum of the N3 Ru dye (dotted curve), of the oxidized N3 dye (dashed curve), both in absolute ethanol, and the difference of these curves (solid curve), (b) Transient transmission signal due to N3 dye molecules anchored to the colloidal TiOj electrode in ultrahigh... 

Figure 4.5 Transient transmission spectra after optical excitation of HBT at 347 nm. The spectra are reconstructed from time traces recorded with probe pulses with different center wavelengths. (Adapted from [3].)...

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