1)

Attosecond Pulse Generation

A state-of-the-art vacuum system for high-order harmonic generation (laser-to-X-ray conversion) will be designed and set up in our laboratory.  Novel ideas will be used to optically deliver attosecond pulses to the experimental region with precise - attosecond - time-delay control.  The system will be technically flexible as to allow multiple experiments on spectral interferometry and coincidence analysis of electrons using reaction microscopes for the detection of correlated quantum dynamics. Your work consists of a mixture of experimental and theoretical work.  When the system becomes operational (expected December 2009), first experiments will shed light on coherent electronic quantum motion on the fastest currently accessible time scales.  Quantum-dynamical computer simulations will be performed to gain insight into the observed processes.  You will be able to work independently and develop your ideas and problem solving skills, while also being part of a team of  scientists and contribute to ongoing experiments in our labs. 

2)

Attosecond Quantum Dynamics and Control (Experiments and Theory)

There is constant opportunity in our group for the observation and modeling of electronic quantum dynamics.  Please inquire by email about current options. 

3)

Design and Setup of an Attosecond Pulse Shaper

Shaping of the coherence properties of light has, in the past, proven capable to control chemical reactions dynamics in molecules.  Transfer of "coherence manipulation"/pulse shaping techniques to the attosecond domain appears promising for the control of the electronic wavefunction itself. A new design for an "attosecond pulse shaper" will be experimentally implemented to test these ideas. 

1)

Femtosecond/Attosecond Pulse Shaping for Coherent Control of Atoms and Molecules

Shaped laser pulses have, in the past, already demonstrated their potential for controlling chemical reactions by manipulating the vibrational dynamics of molecules.  Our goal is to obtain direct control of the electronic wavefunction (the fundamental entity in any kind of chemical bond) by using shaped pulses of light that vary their intensity and frequency on a timescale on the order of attoseconds (10^-18 s) in combination with strong laser fields.

In this lab project, you will work on a novel design for a femtosecond pulse-shaping system to be set up in the lab and perform some first experiments with shaped laser pulses.  The lab project comprises both, lab work and simulations to guide the design process and gain understanding of quantum-mechanical control mechanisms.

In doing so, you will have the opportunity to join a team of experienced scientists and thus be integrated in current ongoing work at a high scientific level.  On the other hand, you can also work independently on various tasks, and thus be able to create your own ideas and solutions and thus contribute to the overall project progress and success.
 

2)

Strong-Field Laser Ionization of Molecules:  Attosecond Quantum Correlation between Nuclear and Electronic Motion

When an intense laser field interacts with atoms or molecules, the electronic structure undergoes dramatic changes.  In particular, ionization can take place by mechanisms such as multiphoton absorption or quantum tunneling through a field-induced Coulomb barrier.  As the period of the (visible) laser field is typically on the order of few femtoseconds (1 fs = 10^-15 s), this happens faster than the  vibrational period of even the lightest molecule (H2, ground state vibrational period is 5 fs).  At the same time, this ionization process is repeated with (half) the period of the laser cycle, which, for several laser cycles can be on the same time scale as the H2 vibrational motion, or even much longer.  As the ionizing electron wavepacket is coherently composed of this series of ionization events, it is an interesting fundamental question to ask in what way the electronic and nuclear quantum  degrees of freedom are correlated (entangled), and how this affects the ionization process.

This project hosted at the Max-Planck Institute for Nuclear Physics will involve quantum-dynamical simulations using existing, customized, and new computer algorithms to solve the time-dependent Schroedinger equation for a coupled electron/internuclear molecular system.  In order to gain a first physical insight into these processes, the dimensionality of the problem will be reduced to 1d.

If time and beamline scheduling permits, experiments will be conducted using Ultrafast Lasers and Reaction Microscopes.

While our workgroup environment will allow you to work with experienced scientists and also to participate in ongoing projects, you will be equally able to concentrate and work independently on this project, developing your own ideas, hypothesis and testing approaches.  When you run into more problematic questions with your project, there will always be support from workgroup colleagues to assist you.
 

3)

Generation of CE-Phase-Stabilized Femtosecond Laser Pulses

A state-of-the-art short-pulse laser system is being set up at the Max-Planck Institute for Nuclear Physics.  This system is devoted to the study of attosecond multi-electron quantum dynamics and coherent control in atoms and molecules.

To reach that goal, the so-called carrier-envelope phase (CEP) of the laser must be stabilized (i.e. the electric field needs to be stable with respect to the laser pulse envelope).  This task represents the main subject of this lab project.  Stability testing and, time permitting, first experiments will be conducted with this CEP-stabilized laser system.

You will have the opportunity to join a team of experienced scientists and thus be integrated in current ongoing work at a high scientific level.  On the other hand, you can also work independently on various tasks, create your own ideas and solutions and thus contribute to the overall project progress and success.
 

4)

Attosecond Pulse Focusing

For time-resolved experiments on the attosecond timescale to be conducted at the Max-Planck Institute for Nuclear Physics, it is necessary to overlap an intense laser pulse with an XUV/soft-x-ray attosecond pulse.  Focusing to a small spot size for both pulses is required in order to reach the strong laser intensities necessary for performing optical-streak camera measurements or other attosecond spectroscopy and control techniques.

Within the scope of this lab project, you will explore and optimize the attosecond-pulse focusing setup, consisting of a toroidal metal mirror and a beam mask for spectral filtering of the attosecond pulse.  Simulations and experiments will be performed to assess the shape of the focal spots of both, laser and attosecond pulses.  This knowledge will immediately be applied and implemented into our attosecond experimental beamline in the lab.

While you will work independently on parts of this project, developing your own ideas and approaches, you will also have the opportunity to work in a team with experienced scientists that can support and assist you.  You will thus also gain an insight into state-of-the-art instrumentation and research on some of the currently most interesting topics of physics -- attosecond science, coherent control, and ultrafast x-rays.