Geometry- and diffraction-independent ionization probabilities in intense laser fields: probing atomic ionization mechanisms with effective intensity matching

Abstract

We report a novel experimental technique for the comparison of ionization processes in ultrafast laser pulses irrespective of pulse ellipticity. Multiple ionization of xenon by 50 fs 790 nm, linearly and circularly polarized laser pulses is observed over the intensity range 10 TW/cm^2 to 10 PW/cm^2 using Effective Intensity Matching (EIM), which is coupled with Intensity Selective Scanning (ISS) to recover the geometry-independent probability of ionization. Such measurements, made possible by quantifying diffraction effects in the laser focus, are compared directly to theoretical predictions of multiphoton, tunnel and field ionization, and a remarkable agreement demonstrated. EIM-ISS allows the straightforward quantification of the probability of recollision ionization in a linearly polarized laser pulse. Furthermore, probability of ionization is discussed in terms of the Keldysh adiabaticity parameter, gamma, and the influence of the precursor ionic states present in recollision ionization is observed for the first time.

10 pages, 5 figures, submitted to Phys. Rev. A on 09-09-05

References in corpus (1)

• Reconstruction of Atomic Ionization Probabilities in Intense Laser Fields

Cited by in corpus (6)

• Atomic excitation during recollision-free ultrafast multi-electron tunnel ionization
• \emph{In situ} measurement of three-dimensional ion densities in focused femtosecond pulses
• Intensity-Resolved Above Threshold Ionization of Xenon with Short Laser Pulses
• Few-photon single ionization of cold rubidium in the over-the-barrier regime
• Controlled redistribution of vibrational population by few-cycle strong-field laser pulses
• On the recollision-free excitation of krypton during ultrafast multi-electron tunnel ionization