Tunnel ionization in three-dimensional tailored light fields

ongoing

Tunneling is a non-resonant, quantum mechanical process without any classical analog. The electric field of a strong laser pulse can bend atomic and molecular potentials such that an electron can be liberated via tunneling. This allows for probing properties of atomic and molecular orbitals with subnanometer and attosecond resolution (like a tunneling microscope’s tip probes properties of the investigated surface). So far, the electric field vector is restricted to a one-dimensional line (1D, e.g. linearly polarized light) or a two-dimensional plane (2D, e.g. circularly polarized light). Since tunneling acts like a filter to the same 1D or 2D subspace in position space, this limits the sensitivity to the 3D structure of the probed orbital. I propose to build an experimental setup that can synthesize 3-dimensional (3D) light fields with peak intensities of up to 1015 W/cm2. 3D light fields will significantly increase the sensitivity of strong field tunneling to the 3D properties of the bound electronic wave function. Further, non-adiabatic dynamics during tunneling and subsequent acceleration, recollision, or recapture of the electronic wave packet will be driven by the time-dependent 3D field as well. This will e.g. allow for the creation of chiral electron distributions in atoms (i.e. chiral atoms), selectively tunnel ionize one enantiomer of a racemic mixture of chiral molecules and enable a new type of pump-probe experiments. The capability to generate 3D light fields will be matched with a 3D detection system, which measures 3D electron momenta in coincidence with ionic fragments. My team and I will use this novel 3D-light-3D-detection-platform to investigate tunnel ionization from atoms, diatomic molecules, and chiral molecules. I anticipate that the proposed experiments will give rise to a new class of experiments on light-matter interaction and provide ground-breaking insight regarding the quantum mechanical process of tunneling itself.