研究目的

To study the signature of two-center interferences in molecular high-order harmonic spectra, with an emphasis on the spectral phase, and to understand how the phase behavior differs for short and long trajectory contributions, linking it to electron dynamics in the continuum and the role of the electric field at recombination time.

研究成果

The research demonstrates that the phase jumps in molecular high-order harmonic spectra are smoothed and depend on the trajectory type (short or long) and the electric field at recombination time. For short trajectories, phase jumps are always smooth and negative, while for long trajectories, they vary with internuclear distance and laser intensity, showing inversion behaviors. The electric field at recombination plays a crucial role, with sharp jumps occurring near zero field. Taylor expansions of molecular SFA provide analytical insights, and prefactor corrections improve agreement with TDSE results. This work highlights the entanglement of structural information and electron dynamics in HHG.

研究不足

The study is limited to 1D models and homonuclear diatomic molecules, which may not fully capture 3D effects or more complex molecular systems. The use of approximations like LCAO and plane waves in SFA can lead to discrepancies, and error compensations between approximations are noted. The short laser pulse used does not produce a harmonic comb structure, and the cutoff region limits observation of full phase jumps for low intensities.