Femtolab group is a primarily experimental laser physics / physical chemistry group located at the Department of Chemistry, Aarhus University. The group focuses on research in quantum control and reaction dynamics of molecules, atoms and ions in liquid helium droplets. 

Helium nanodroplets are nanometer-sized clusters of liquid helium that are ultra-cold (< 0.4 K), transparent into the UV, and superfluid. These properties make the droplets ideal for isolating single molecules or atoms in a cold environment.

Quantum control is achieved using femtosecond (10^-15 s) to nanosecond (10^-9 s) laser pulses, which induce rotational dynamics (alignment), vibrational motion and/or electronic excitation of the isolated molecules or atoms. A subsequent laser pulse is used to multiply ionize the system, which causes the charges to repel in a Coulomb explosion event. 

The ions are measured using a velocity-map imaging spectrometer and recorded with a Tpx3Cam, an ultrafast, event-based camera that records the arrival time and position of all ions, shot-by-shot. The data is visualized and analyzed using various statistical techniques.

Theoretical simulations of light-matter interactions, molecular dynamics simulations of molecules and their Coulomb explosion trajectories and quantum chemistry computations are used to quantify and model the experimental work. This is developed both in the group and with international collaborators.

Research in the group also includes: study of deflection of neutral species using an inhomogenous electric field; gas-phase dynamics using pulsed valves; development of electronics, sample generation methods and software; data analysis methods for large datasets.

Currently, the group consists of group leader Henrik Stapelfeldt, one AC-TAP, three PhD students and one PostDoc.