M Yu Emelin et al 2008 New J. Phys. 10 025026 doi:10.1088/1367-2630/10/2/025026
M Yu Emelin, M Yu Ryabikin1 and A M Sergeev
Show affiliationsPart of Focus on Attosecond Physics
We present a method for probing ultrafast nuclear dynamics in molecules using transient enhancement of high-order harmonic generation (HHG). The method exploits strong dependence of the overall harmonic yield in a fixed spectral range on the nuclear separation in a molecule, which is shown to take place for both aligned and randomly oriented molecules. Our numerical simulations show that this method is capable of monitoring long-term evolution of the nuclear vibrational wave packets in molecules, even in light-weight ones, with very high time resolution. By the example of D2+ vibrational wave packet launched via tunnelling ionization of D2 and probed by a time-delayed 8 fs laser pulse with λ = 800 nm and the peak intensity of 1014 W cm-2, we show that the time-delay dependence of the high harmonic signal exhibits pronounced features, which are due to the collapses and revivals of the nuclear wave packet. The time-frequency analysis of the pump–probe signal reveals structures with a periodicity down to 6 fs, which correspond to the fractional revivals of orders 1/5 and 1/10. With the laser parameters used, the deuteron motion during the probe pulse is shown to have almost negligible effect on the resulting signal.
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
33.15.Mt Rotation, vibration, and vibration-rotation constants
33.80.Eh Autoionization, photoionization, and photodetachment
Issue 2 (February 2008)
Received 15 September 2007
Published 29 February 2008
M Yu Emelin et al 2008 New J. Phys. 10 025026
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