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Strong-field lightâ€"matter interactions initiate a wide range of phenomena in which the quantum paths of electronic wavepackets can be manipulated by tailoring the laser field. Among the electrons released by a strong laser pulse from atomic and molecular targets, some are subsequently driven back to the vicinity of the ionic core by the oscillating laser field. The trajectories of these returning electrons are bent toward the core by the ionic potential, an effect known as Coulomb focusing. This process, studied over the past two decades, has been associated with the long range influence of the Coulomb potential. Here we explore the structural properties of the Coulomb focusing phenomenon. Specifically, we numerically study the sensitivity of the returning electron dynamics to the anisotropy of the ionic potential. We employ orthogonally polarized two-color strong fields and chiral molecules, whose asymmetric features lead to unambiguous fingerprints of the potential on the freed electrons. The Coulomb-focused electrons show an enhanced sensitivity to chirality, related to an asymmetric attoclock-like angular streaking stemming from field-assisted scattering of the electrons onto the chiral ionic potential. Anisotropic features of the ionic potential thus monitor the motion of Coulomb-focused electrons throughout their returning paths, shedding light on the structural properties of the interaction. [ABSTRACT FROM AUTHOR]

While high harmonic generation from atoms is relatively well understood, the ability to align gas-phase molecules opens an opportunity to more deeply understand the underlying physics. Many assumptions, such as the single active electron approximation, neglect of the Coulomb potential, the strong field approximation, and the assumption of plane waves, are being challenged by new experimental observations. We study high harmonic emission from aligned molecules such as N2, O2 and CO2. We present experimental measurements of the amplitude of the emission as a function of molecular angle, as well as the polarization state. [ABSTRACT FROM AUTHOR]