Coherent Control at Its Most Fundamental: Carrier-Envelope-Phase-Dependent Electron Localization in Photodissociation of aH2+Molecular Ion Beam Target

Abstract

Measurements and calculations of the absolute carrier-envelope-phase (CEP) effects in the photodissociation of the simplest molecule, H2(+), with a 4.5-fs Ti:sapphire laser pulse at intensities up to (4±2)×10(14) W/cm2 are presented. Localization of the electron with respect to the two nuclei (during the dissociation process) is controlled via the CEP of the ultrashort laser pulses. In contrast to previous CEP-dependent experiments with neutral molecules, the dissociation of the molecular ions is not preceded by a photoionization process, which strongly influences the CEP dependence. Kinematically complete data are obtained by time- and position-resolved coincidence detection. The phase dependence is determined by a single-shot phase measurement correlated to the detection of the dissociation fragments. The experimental results show quantitative agreement with ab initio 3D time-dependent Schrödinger equation calculations that include nuclear vibration and rotation.

The plateau in above-threshold ionization: the keystone of rescattering physics

“…Obviously, this can only happen in between adjacent ATI peaks-where the yield is low [146]. Nevertheless, the concept can be applied for, e.g., coherent control by few-cycle pulses [147]. In the strong-field regime, the situation is hardly more favorable: the high nonlinearity of tunnel ionization can certainly lead to strongly different ionization yield within subsequent optical half-cycles with opposite field direction.…”

Real-time, single-shot, carrier-envelope-phase measurement of a multi-terawatt laser

“…The CEP has been shown to be capable of controlling the ionization of atoms [2], the generation of attosecond pulses [3], and the dissociation and ionization dynamics of small [4,5] and more complex molecules [6]. More recently, CEP effects were found to influence strong-field interaction with nanotips [7], clusters [8] and solids [9].…”

“…phase tagging, seems to be an ideal way towards the investigation and control of CEP-sensitive interactions in this regime. Phase tagging has already proven to be instrumental for experiments with low-power laser systems, particularly when data acquisition times become longer than the period over which the laser performance can be kept constant [5,16]. The phase-tagging approach is reminiscent of the procedure in pumpprobe experiments involving femtosecond lasers at FELs, where the arrival time delay between X-rays and optical laser is measured for each shot and subsequently the data points are sorted and re-binned with respect to this delay [17,18].…”

Momentum-resolved study of the saturation intensity in multiple ionization

“…The ellipticity, ε, is adjusted by a quarter-wave plate. The three-dimensional momentum distributions are reconstructed from the time and position information recorded for each ion by a delay-line detector [18].The ion momentum distributions measured for different ellipticities in the polarization plane of the laser for the cases of single, double, triple and quadruple ionization of Ne + are shown in Fig. …”