Transient grating harmonic

Fig. 3. (a) The temporal dependence of the dillraclion of a CW He-Ne laser from a transient grating induced by two nano.second Nd YAG second harmonic laser pulses in a nematic film (PCB 40 m thick io-meotropically aligned) (after [17]). Time scale is 20 ns/div. Similar ultrasonic wave generation was also observed in a smectic liquid crystal film 117bj. (b) The dynamics of the thermal grating formation and decay in a nematic film as monitored by a CW He-Ne probe laser diffraction. The grating wave vector K - K2 is perpendicular to the director axis, (c) Same as in (b), but for K K2 along the director axis. 

Fig. 5.33 Measured signal from high-harmonic transient grating spectroscopy of NO2 (left) and computed diabatic state population (right). Reprinted form [221. (Reprinted with permission from P. M. Kraus et al., Phys. Rev. A 85, 043409 (2012)).

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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