Synopsis: The long and short of it

Ultrafast optical probing of an ionized molecule with different pulse durations reveals details of the dynamics of vibrational excitations.
Synopsis figure
Illustration: F. Kelkensberg et al., Phys. Rev. Lett. (2009)

As laser pulses get shorter and shorter, physicists are able to study the internal dynamics of a molecule with a level of detail far beyond previous expectations. The advent of attosecond laser physics has enabled researchers to accurately create an electronic or vibrational excitation in molecules, which may then be tracked by other optical pulses as the excitation evolves. So far, however, it has turned out to be a challenge to prepare reproducible attosecond wave packets in molecules with sufficient signal above the noise. In addition, the high fields used for the probe laser often tend to perturb the system, which hampers a correct analysis of the results.

In their report in Physical Review Letters, Freek Kelkensberg and colleagues at the FOM Institute for Atomic and Molecular Physics in Amsterdam, The Netherlands, and collaborators in Canada and Europe demonstrate a method that solves both these problems. Using state-of-the-art 400-attosecond XUV pulses, the authors ionize hydrogen molecules and launch a vibrational wave packet in the resulting molecular ion. The ultrafast dynamics of these wave packets are subsequently probed by intense femtosecond infrared pulses. For longer pulses the wave packets propagate adiabatically, whereas for shorter pulses the creation, dephasing, and revival of vibrational wave packets is observed. These results show the importance of pulse duration in the analysis of strong field molecular dynamics and reveal the onset of adiabaticity in the dissociative ionization of molecular hydrogen, leading to a detailed understanding of the elementary bond-breaking process in molecules. – Deniz van Heijnsbergen


Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsOptics

Previous Synopsis

Next Synopsis

Related Articles

Viewpoint: Ionization Delays That Stand Out
Optics

Viewpoint: Ionization Delays That Stand Out

Attosecond-resolution experiments have determined the delay in an electron’s emission from a molecule after being ionized with light. Read More »

Focus: Giant Molecule Made from Two Atoms
Atomic and Molecular Physics

Focus: Giant Molecule Made from Two Atoms

Experiments confirm the existence of 1-micrometer-sized molecules made of two cesium atoms by showing that their binding energies agree with predictions.   Read More »

Focus: Choose the Number of Atoms in Your Cloud
Atomic and Molecular Physics

Focus: Choose the Number of Atoms in Your Cloud

A new technique allows researchers to specify the number of atoms in an ultracold cloud (in the millions) and then to reproduce that same number in repeated experiments. Read More »

More Articles