Tunnel ionization in three-dimensional tailored light fields

Projektbeschreibung

Wie Quantenteilchen scheinbar unüberwindbare physische Barrieren in 3D überwinden

In der Quantenmechanik können Elektronen durch atomare und molekulare Potentiale freigesetzt werden, die durch starke Laserpulse gebogen werden. Dieser Prozess wird als Tunnelionisation bezeichnet und hat kein klassisches Analogon. Das elektrische Feld der Laserpulse war bisher auf eine 1D-Linie oder eine 2D-Ebene beschränkt. Im Rahmen des ERC-finanzierten Projekts 3DTunneling wird ein Versuchsaufbau eingerichtet, der 3D-Lichtfelder synthetisieren kann, und es wird ein neuartiges 3D-Detektionssystem zur Untersuchung der Tunnelionisation von Atomen, zweiatomigen Molekülen und chiralen Molekülen entwickelt. Diese neuartige 3D-Licht/3D-Detektionsplattform wird die Empfindlichkeit des Starkfeldtunnelns auf die 3D-Eigenschaften atomarer und molekularer Orbitale mit einer Auflösung im Sub-Nanometer- und Attosekundenbereich erhöhen.

Ziel

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 microscopes 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.