Accurate in situ Measurement of Ellipticity Based on Sub-cycle Ionization Dynamics

Abstract

Elliptically polarized laser pulses (EPLPs) are widely applied in many fields of ultrafast sciences, but the ellipticity~($\epsilon$) has never been in situ measured in the interaction zone of the laser focus. In this work, we propose and realize a robust scheme to retrieve the $\epsilon$ by temporally overlapping two identical counter-rotating EPLPs. The combined linearly electric field is coherently controlled to ionize Xe atoms by varying the phase delay between the two EPLPs. The electron spectra of the above-threshold ionization and the ion yield are sensitively modulated by the phase delay. We demonstrate that these modulations can be used to accurately determine $\epsilon$ of the EPLP. We show that the present method is highly reliable and is applicable in a wide range of laser parameters. The accurate retrieval of $\epsilon$ offers a better characterization of a laser pulse, promising a more delicate and quantitative control of the sub-cycle dynamics in many strong field processes.

Phys. Rev. Lett., in press (2018), 4 figures

References in corpus (1)

• Electron spin polarization in strong-field ionization of Xenon atoms

Cited by in corpus (1)

• Decoding electron tunnelling delay time by embracing wave-particle duality