Project Details
Projekt
Ionization Channel-Resolved Molecular Orbital Imprint in Laser-Driven Electron Rescattering
Applicant
Professor Dr. Jochen Mikosch
Subject Area
Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
Term
since 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 411026426
During the last few years, the facility in tailoring intense laser pulses has been revolutionizing the atomic and molecular attosecond strong-field spectroscopies. Their essence is captured by the well-known and widely-used three-step model. The three steps consist of laser-driven tunnel ionization, propagation of the electron in the continuum and its interaction with the ion core upon recollision. All of these steps occur consecutively within a fraction of a laser cycle. In our recent work on laser-driven electron rescattering we have examined the central assumption that recollision occurs for the same fraction of ionization events, regardless of the molecular orientation with respect to the laser polarization. We base our experiments on the separation of laser-driven electron rescattering into different strong-ionization continua in a single molecule.Our recent results do potentially have important consequences for Laser-Induced Electron Diffraction (LIED) of molecules, an emerging technique in which molecules are self-imaged by one of their own electrons. LIED promises to become a time-resolved variant of conventional diffraction with electron beams, a powerful method to obtain structural information on molecules. In standard LIED analyses it is assumed that the crucial molecular frame dependence of the amplitude of the returning wavepacket is simply given by the molecular frame dependence of the strong-field ionization probability. This assumption is in marked contrast with our recent experimental and theoretical finding that recollision occurs for a molecular-frame dependent fraction of the ionized electrons.Here we propose to quantitatively explore the sensitivity of the LIED molecular structure determination to the molecular-frame dependence of the return probability. To achieve this objective, we want to perform a molecular structure analysis separately for two molecular strong-field ionization channels. Moreover, we aim to extend our recent partial reconstruction of the molecular-frame dependence of the electron rescattering probability to a full reconstruction. This will access both the polar angle and the azimuthal angle separately for each ionization channel. Furthermore, we plan to control the continuum trajectory of the propagating continuum electron by manipulating the strong laser field. This would allow us to steer different parts of the electron wavepacket to recollision, thus characterizing its structure which depends on the molecular orbitals and their response to the strong laser field. Finally, we plan study the inelastic rescattering of the laser-driven continuum electron with its ion to better understand their interaction.The research proposed here is crucial for understanding laser-induced electron rescattering in detail, a prerequisite for confidently harnessing LIED into a powerful time-resolved probe of molecular dynamics and chemistry.
DFG Programme
Priority Programmes
