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Helml, Wolfram, Dr.

Wolfram Helml

Ludwig-Maximilians-Universität (LMU)

Fakultät für Physik, Lehrstuhl für Experimentalphysik –Laserphysik
Am Coulombwall 1

85747 Garching, Germany

Phone: +49 (0)89 289-12861

MAP research areas: 

A.3 Laser-based high-energy particle and x-ray sources

A.3.2 Laser-driven electron acceleration and its use for brilliant X-ray generation


Research expertise and Current Interests:

Higher-order harmonic generation (HHG) with various laser wavelengths and geometries

Control & measurement of carrier–envelope phase (CEP) and field-dependent aspects for few-cycle laser pulses

Investigation of electron dynamics in gases, liquid jets and on surfaces of solids by attosecond streaking spectroscopy

Development of light sources in the vacuum ultraviolet (VUV) region (200 nm to 160 nm wavelengths) with temporal durations below 10 fs to uncover molecular dynamics on the sub-10 fs timescale

Demonstrating a laser-driven free-electron laser (FEL) in the frame of the Centre for Advanced Laser Applications (CALA) and investigating its potential for measurements of ultrafast structural changes and diagnostic medical applications

Direct time domain characterization of single-shot pulse durations and relative shot– to–shot arrival times at free-electron lasers such as the Linac Coherent Light Source (LCLS) with few-femtosecond to sub-femtosecond precision

Dynamics of free electrons and their relaxation pathways in liquid water, including ensuing structural reactions of organic molecules in aqueous solutions, e.g. DNA damage by exposure to UV or X-ray radiation

Understanding fundamental quantum phenomena and their relation to processes in our classical, everyday world by the interaction of tailored light pulses with microscopic degrees of freedom of macroscopic systems, e.g. in an optomechanical setup

Experimenting with novel approaches for multi-dimensional X-ray spectroscopy, i.e.generation of variable delay, two-colour double pulses with few-femtosecond or subfemtosecond durations at FELs by temporal and spectral shaping of the electron heater beam or use of slotted foils in the electron beam path




2007 Diploma in physics, Institute for Theoretical Physics, Universität Wien
2012 PhD in physics, TUM and Max Planck Institute of Quantum Optics
2012 - 2014 Marie-Curie research fellow (Outgoing Phase), Standford University, Menlo Park, CA, USA
2014 - 2016 Marie-Curie research fellow (Return Phase), TUM, Garching
2016 - present Project leader at the LUX beam line for the Centre of Advanced Laser Applications (CALA) in Munich



Selected publications:

“Circular Dichroism Measurements at an X-ray Free-Electron Laser with Polarization Control”

G. Hartmann, A. O. Lindahl, A. Knie, N. Hartmann, A. A. Lutman, J. P. MacArthur, I. Shevchuk, J. Buck, A. Galler, J. M. Glownia, W. Helml, Z. Huang, N. M. Kabachnik, A. K. Kazansky, A. Marinelli, T. Mazza, H.-D. Nuhn, P. Walter, J. Viefhaus, M. Meyer, S. Moeller, R. N. Coffee & M. Ilchen
Review of Scientific Instruments 87, 083113 (2016)


“Generating femtosecond X-ray pulses using an emittance-spoiling foil in free-electron lasers”
Y. Ding, C. Behrens, R. Coffee, F.-J. Decker, P. Emma, C. Field, W. Helml, Z. Huang, P. Krejcik, J. Krzywinski, H. Loos, A. Lutman, A. Marinelli, T. J. Maxwell & J. Turner
Applied Physics Letters 107, 191104 (2015)


“Measuring the temporal structure of few-femtosecond free-electron laser X-ray pulsesdirectly in the time domain”
W. Helml*, A. R. Maier*, W. Schweinberger, I. Grguras, P. Radcliff, G. Doumy, C. Roedig, J. Gagnon, M. Messerschmidt, S. Schorb, C. Bostedt, F. Grüner, L. F. DiMauro, D. Cubaynes, J. D. Bozek, T. Tschentscher, J. T. Costello, M. Meyer, R. Coffee, S. Düsterer, A. L. Cavalieri & R. Kienberger
Nature Photonics 8, 950–957 (2014)