Two-color ionization of hydrogen by short intense pulses

TL;DR

This paper investigates how two short pulses in infrared and XUV frequencies influence hydrogen ionization, revealing quantum interference effects and spectral ripples dependent on pulse duration and timing.

Contribution

It provides a detailed analysis of photoelectron spectra resulting from two-color ionization, highlighting the impact of pulse parameters on spectral features and temporal shape inference.

Findings

Spectral ripples separated by infrared photon energy depend on X-ray pulse duration.

Quantum interference effects explain features in long pulse spectra.

Photoelectron spectra breadth reveals the temporal shape of low-frequency radiation.

Abstract

Photoelectron energy spectra resulting by the interaction of hydrogen with two short pulses having carrier frequencies, respectively, in the range of the infrared and XUV regions have been calculated. The effects of the pulse duration and timing of the X-ray pulse on the photoelectron energy spectra are discussed. Analysis of the spectra obtained for very long pulses show that certain features may be explained in terms of quantum interferences in the time domain. It is found that, depending on the duration of the X-ray pulse, ripples in the energy spectra separated by the infrared photon energy may appear. Moreover, the temporal shape of the low frequency radiation field may be inferred by the breadth of the photoelectron energy spectra.