Research Groups
Manfred Lein

Manfred Lein's Research Group

The Lein group does research on atoms and molecules in ultrafast external fields, mostly in the regime of strong laser fields where perturbation theory is not applicable. The control of quantum mechanical dynamics on the femtosecond to attosecond time scale and Ångström spatial scale are two essential aspects of our work.

For more information, please scroll down or visit Manfred Lein's external profile pages:

Persons

Gina Gerlach
Office
Address
Appelstraße 2
30167 Hannover
Building
Room
245
Address
Appelstraße 2
30167 Hannover
Building
Room
245
Cornelia Greese
Administrative/Technical Staff
Address
Appelstraße 2
30167 Hannover
Building
Room
216
Address
Appelstraße 2
30167 Hannover
Building
Room
216
Dr. Nikolay Shvetsov-Shilovskiy
Research Staff
Address
Appelstraße 2
30167 Hannover
Building
Room
212
Address
Appelstraße 2
30167 Hannover
Building
Room
212
M. Sc. Simon Brennecke
Doctoral Candidates
Address
Appelstraße 2
30167 Hannover
Building
Room
209
Address
Appelstraße 2
30167 Hannover
Building
Room
209
M. Sc. Paul Winter
Doctoral Candidates
Address
Appelstraße 2
30167 Hannover
Building
Room
237
Address
Appelstraße 2
30167 Hannover
Building
Room
237
M. Sc. Zeinab Hardani
Doctoral Candidates
Address
Appelstraße 2
30167 Hannover
Building
Room
230
Address
Appelstraße 2
30167 Hannover
Building
Room
230

Research

Three good reasons why the response of atoms and molecules to strong light pulses is a subject of ongoing research are the following:

electron trajectories electron trajectories electron trajectories

i- The laser-induced dynamics follows and reveals the laws of quantum mechanics with explicitly time dependent Hamiltonian in a regime where low-order time-dependent perturbation theory is not applicable. Strong-field dynamics in combination with Coulomb-interacting particles remains a challenge for theoretical study and often requires substantial numerical effort. At the same time, laser-driven atoms can show behaviour that is reasonably but not accurately enough explained by classical mechanics leading into the interesting regime where classical and quantum physics meet. Electrons that leave their parent ion after ionization by a field with low frequency and high field strength fall into this category.

ii- The ability to shape the incident field by adjusting a multitude of parameters such as intensity, wavelength, pulse duration, carrier-envelope phase, polarization, spectral composition and pulse shape allows us to control microscopic dynamics on ultrafast time scales. Ultimate goals of quantum control are the laser-based steering of chemical reactions and the controlled emission of charged particles and coherent radiation.

High-harmonic generation High-harmonic generation High-harmonic generation

iii- Laser-irradiated atoms and molecules serve as a source of coherent high-frequency radiation with photon energies reaching from the UV into the X-ray range. This conversion process is known as high-harmonic generation and provides the basis for the formation of attosecond pulses,  i.e. coherent pulses with durations below one femtosecond or even below 100 attoseconds. We know also that harmonic generation is due to laser-driven electrons that spend a sub-laser-cycle excursion time in an unbound state before returning into their initial bound state. The dependence of the excursion time on the photon energy offers the possibility to read attosecond-scale dynamics of the parent ion from the observed radiation.