Wavepacket propagation, phase-coherent

When a femtosecond laser pulse passes through nearly any medium, coherent vibrational excitation (in general, initiation of coherent wavepacket propagation) is likely [33, 34]. One- or two-photon absorption of a visible or ultraviolet pulse into an electronic excited state can result in phase-coherent motion in the excited-state potential [35]. Impulsive stimulated Raman scattering can initiate phase-coherent vibrational motion in the electronic... 

Fig. 6.13. The polariton wavepacket, created by coherent scattering of picosecond laser and Stokes pulses, propagates in the crystal at the angle 0 with respect to the excitation direction. This angle is determined by the excitation wavevector geometry (see above). The coherent amplitude of the propagating wavepacket may be measured by phase-matched coherent anti-Stokes scattering of a probe pulse suitably delayed in time (fn) and displaced in space (by Xn)- Reprinted with permission from Gale et al. (68). Copyright (1986), American Physical Society.

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