Studying the universality of field induced tunnel ionization times via high-order harmonic spectroscopy

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Vol. 47; no. 20; pp. 204029 - 5
• Main Authors: Soifer, H, Bruner, B D, Negro, M, Devetta, M, Faccialà, D, Vozzi, C, Silvestri, S de, Stagira, S, Dudovich, N
• Format: Journal Article
• Language: English
• Published: IOP Publishing 28.10.2014
• Subjects: Approximation; Atomic structure; attosecond spectroscopy; Dynamical systems; Dynamics; high harmonic generation; Ionization; ionization times; Mathematical analysis; mid-IR; Spectroscopy; tunnel ionization; Tunnels (transportation)
• ISSN: 0953-4075; 1361-6455
• DOI: 10.1088/0953-4075/47/20/204029

High-harmonic generation spectroscopy is a promising tool for resolving electron dynamics and structure in atomic and molecular systems. This scheme, commonly described by the strong field approximation, requires a deep insight into the basic mechanism that leads to the harmonic generation. Recently, we have demonstrated the ability to resolve the first stage of the process-field induced tunnel ionization-by adding a weak perturbation to the strong fundamental field. Here we generalize this approach and show that the assumptions behind the strong field approximation are valid over a wide range of tunnel ionization conditions. Performing a systematic study-modifying the fundamental wavelength, intensity and atomic system-we observed a good agreement with quantum path analysis over a range of Keldysh parameters. The generality of this scheme opens new perspectives in high harmonics spectroscopy, holding the potential of probing large, complex molecular systems.