Events - today, tomorrow ... soon Highlights and News
today: 2017/09/25
Seminarraum, Raum 2.01, Haus A, 14:00 h   MD JANIBUL ALAM SOEB, PhD applicant
LP3- Lasers, Plasmas and Photonic Processes, Marseille, France
Micro-explosions Induced by Infrared Femtosecond Laser Inside Silicon
8 September 2017: First imaging of free nanoparticles in laboratory experiment using a high-intensity laser source
In a joint research project, scientists from the Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI), the Technische Universität Berlin (TU) and the University of Rostock have managed for the first time to image free nanoparticles in a laboratory experiment using a high-intensity laser source. Previously, the structural analysis of these extremely small objects via single-shot diffraction was only possible at large-scale research facilities using so-called XUV and x-ray free electron lasers. Their pathbreaking results facilitate the highly-efficient characterisation of the chemical, optical and structural properties of individual nanoparticles and have just been published in "Nature Communications". The lead author of the publication is junior researcher Dr Daniela Rupp who carried out the project at TU Berlin and is now starting a junior research group at MBI. ...more.
1 September 2017: Aspirin tablets help unravel basic physics
Aspirin in form of small crystallites provides new insight into delicate motions of electrons and atomic nuclei. Set into molecular vibration by strong ultrashort far-infrared (terahertz) pulses, the nuclei oscillate much faster than for weak excitation. They gradually return to their intrinsic oscillation frequency, in parallel to the picosecond decay of electronic motions. An analysis of the terahertz waves radiated from the moving particles by in-depth theory reveals the strongly coupled character of electron and nuclear dynamics characteristic for a large class of molecular materials. ...more.
13 July 2017: Water makes the proton shake - ultrafast motions and fleeting geometries in proton hydration
Basic processes in chemistry and biology involve protons in a water environment. Water structures accommodating protons and their motions have so far remained elusive. Applying ultrafast vibrational spectroscopy, Dahms et al. map fluctuating proton transfer motions and provide direct evidence that protons in liquid water are predominantly shared by two water molecules. Femtosecond proton elongations within a hydration site are 10 to 50 times faster than proton hopping to a new site, the elementary proton transfer step in chemistry.. ...more.
22 June 2017: A powerful laser system for driving sophisticated experiments in attosecond science
Attosecond science has revolutionized the way we look into the time-dependent evolution of the microscopic world, where the behaviour of matter is governed by the rules of quantum mechanics. The technological breakthrough that made possible the development of the field is based on the generation of ultra-short laser pulses that last only a few oscillations of the electric field. These short pulses have a focused intensity where the electric field is comparable to the one electrons experience inside atoms and molecules. It is possible to control both the exact temporal shape and the waveform of these ultra-short pulses. While ultra-short laser pulses have been used in a few laboratories worldwide to study light-induced dynamics in atoms and molecules, many questions remain unanswered, due to the low data rates and inherently low SNR achievable with current state-of-the-art laser systems. At the Max Born Institute, a powerful laser system has now been completed, capable of reproducing the parameters of laser systems typically used in attosecond science experiments, but with a 100 times higher pulse repetition rate. This new laser system enables an entirely new class of experiments in simple atomic and small molecular systems, as well as high fidelity investigations of more complex molecules. ...more.
16 June 2017: A perfect attosecond experiment
Attosecond science techniques are currently revolutionizing ultrafast laser physics research, and enable experiments that provide unprecedented insights into the structure and time-dependent dynamics of electrons in atoms, molecules and condensed phase systems. In a new experiment, physicists from Waseda University (Japan), the National Research Council (Canada) and the Max Born Institute (Germany) have used attosecond science techniques to fully characterize the quantum mechanical wave function of an electron that is formed by photoionization. The work, reported in Science, is the first example of a "perfect" experiment using attosecond technology. ...more.
22 May 2017: Turmoil in sluggish electrons' existence
An international team of physicists has monitored the scattering behavior of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as 'sluggish'. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence relatively still in a dielectric crystal lattice. This idyll has now been heavily shaken up by a team of physicists from various research institutions, including the Laboratory of Attosecond Physics (LAP) at the Ludwig-Maximilians-Universität Munich (LMU) and the Max Planck Institute of Quantum Optics (MPQ), the Institute of Photonics and Nanotechnologies (IFN-CNR) in Milan, the Institute of Physics at the University of Rostock, the Max Born Institute (MBI), the Center for Free-Electron Laser Science (CFEL) and the University of Hamburg. For the first time, these researchers managed to directly observe the interaction of light and electrons in a dielectric, a non-conducting material, on timescales of attoseconds (billionths of a billionth of a second). ...more.
12 April 2017: Thomas Fennel started as a Heisenberg fellow at the MBI
Prof. Thomas Fennel, group leader at the Institute of Physics at the University of Rostock, has been awarded a prestigious Heisenberg Fellowship funded by the Deutsche Forschungsgemeinschaft (DFG). With the Heisenberg fellowship, which officially started on January 1st 2017, the DFG is supporting a research project to explore new routes for imaging and controlling ultrafast electronic motion in nanostructures. The underlying research will be carried out in a joint effort between Prof. Fennel's team at the University of Rostock and researchers in division A of the Max Born Institute, which is led by Prof. Marc Vrakking and to which Prof. Fennel is affiliated as an associated researcher. ...more.
14 March 2017: Nanostructures give directions to efficient laser-proton accelerators
Nanostructured surfaces have manifold applications. Among others they are used to selectively increase aborption of light. You can find them everywhere, where light harvesting is the key point, e.g. in photovoltaics. But also in laser proton acceleration this approach attracts a lot of attention as nanostructured targets hold the promise to significantly increase maximum proton energies and proton numbers at a given laser energy. As for any other new technology, a high efficiency is a key for a potential future use. Scientists at the Max-Born-Institute (MBI) in Berlin have now investigated, under which conditions the use of nanostructures in laser ion acceleration is beneficial. ...more.
8 February 2017: Lattice of nanotraps and line narrowing in Raman gas
Decreasing the emission linewidth from a molecule is one of the key aims in precision spectroscopy. One approach is based on cooling molecules to near absolute zero. An alternative way is to localize the molecules on subwavelength scale. A novel approach in this direction uses a standing wave in a gas-filled hollow fibre. It creates an array of deep, nanometer-scale traps for Raman-active molecules, resulting inlinewidth narrowing by a factor of 10 000. ...more.
1st February 2017: Ultrasmall atom motions recorded with ultrashort x-ray pulses
Periodic motions of atoms over a length of a billionth of a millionth of a meter (10-15 m) are mapped by ultrashort x-ray pulses. In a novel type of experiment, regularly arranged atoms in a crystal are set into vibration by a laser pulse and a sequence of snapshots is generated via changes of x-ray absorption. ...more.
5 January 2017: Unified time and frequency picture of ultrafast atomic excitation in strong fields
The insight that light sometimes needs to be treated as an electromagnetic wave and sometimes as a stream of energy quanta called photons is as old as quantum physics. In the case of interaction of strong laser fields with atoms the dualism finds its analogue in the intuitive pictures used to explain ionization and excitation: The multiphoton picture and the tunneling picture. In a combined experimental and theoretical study on ultrafast excitation of atoms in intense short pulse laser fields scientists of the Max Born Institute succeeded to show that the prevailing and seemingly disparate intuitive pictures usually used to describe interaction of atoms with intense laser fields can be ascribed to a single nonlinear process. Moreover, they show how the two pictures can be united. The work appeared in the journal Physical Review Letters and has been chosen to be an Editors' suggestion for its particular importance, innovation and broad appeal. Beside the fundamental aspects the work opens new pathways to determine laser intensities with high precision and to control coherent Rydberg population by the laser intensity. ...more.
5 January 2017: Amplification of relativistic Electron Pulses by Direct Laser Field Acceleration
Controlled direct acceleration of electrons in very strong laser fields can offer a path towards ultra-compact accelerators. Such a direct acceleration requires rectification and decoupling of the oscillating electromagnetic laser field from the electrons in a suitable way. Researchers worldwide try to tackle this challenge. In experiments at the Max Born Institute, direct laser acceleration of electrons could now be demonstrated and understood in detail theoretically. This concept is an important step towards the creation of relativistic and ultra-short electron pulses within very short acceleration distances below one millimeter. Resulting compact electron and related x-ray sources have a broad spectrum of applications in spectroscopy, structural analysis, biomedical sciences and for nanotechnology. ...more.


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