Third-order dispersion

FIGURE 8.1 Time-domain effects of the second- and third-order dispersion. A TL pulse is one that is as short as possible given the available bandwidth. GDD causes time separation between different wavelengths of the pulse, and this broadens its duration. Third-order dispersion breaks the laser pulse into different sub-pulses in the time domain. 

The term that depends on the third power of the frequency shift is known as third-order dispersion (TOD). When a TL pulse acquires a significant amount of TOD, the pulse envelope is distorted and a series of sub-pulses is produced, as shown in Figure 8.1. Unlike a pulse with SOD, a pulse with TOD leads to two-photon excitation with the same efficiency as a TL pulse but only for a particular two-photon frequency. At other frequencies, the amount of excitation is suppressed. The control over TOD would allow for preferential excitation in different spectral regions, while its correction would lead to efficient two-photon excitation over the whole accessed spectral range. Unfortunately, measuring and correcting TOD is not a simple task. 

Fig. 7.9. Dependence of the fragment ion yield ratio of m2g/m3i on third-order dispersion coefficient...

The orbitals p and x are on C and, as before, k and / are on A and m, n on B. For the interaction of three spherically symmetric atoms the third-order dispersion nonadditivity contains the famous Axilrod-Teller-Muto triple-dipole interaction311,312. 

Additivity of the Second-order Dispersion Energy Non-additivity of the Third-order Dispersion Interaction... 

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