Transient grating and interferometry

When the probe pulse generates high-harmonics from this mixed sample, the signals from the excited and unexcited population interfere, causing diffracted signals at the detector. Thus the relative phase difference between the excited and unexcited populations is be foimd in the diffraction pattern. In particular, when the pump pulse creates a vibrational wavepacket in both the ground and excited electronic states [221], the zero-order diffraction signal. 

3 Transient grating interferometry of the conical intersection dynamics in NO2 

In Refs. [466] and [221], the transient grating interferometry signal from the conical intersection dynamics in NO2 (see Sec. 5.4.1.2) was measured for a 401 nm (3.09 eV), FWHM 40 fs pump pulse. The left panel of Fig. 5.33 shows the time-dependence of Im= , t) for the 13th harmonic, which re-hects the time evolution of the diabatic excited state population (Fig. 5.33, right). In the case of ionization out of the same orbital and spatially spread vibrational waveftmction as in the present case, the dependence of di Q,t) on the molecular geometry (vibrational dynamics) was found to be small 

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