12 July 2017 Congratulations to New ICFO PhD graduate

Dr. Matthias Baudisch

Thesis Committee

Dr. Matthias Baudisch graduated with a thesis in “High Power, High Intensity Few-Cycle Pulses in the Mid-IR for Strong-Field Experiments” Dr. Matthias Baudisch received his Diplom-Physiker degree from the Technical University in Dresden, Germany, before joining the Attoscience and Ultrafast Optics research group led by ICREA Prof. at ICFO Jens Biegert. At ICFO, he centered his doctoral work on studying and improving the performance of current high power, mid-IR OPCPA systems to overcome existing limitations and to match and even exceed the capabilities of similar visible and near-IR radiation sources. Dr. Matthias Baudisch’s thesis, entitled “High Power, High Intensity Few-Cycle Pulses in the Mid-IR for Strong-Field Experiments” has been supervised by Prof. Dr. Jens Biegert.


High energy, few-cycle, mid-IR radiation sources featuring high pulse repetition rates are of tremendous interest for a variety of strong-field physics and attoscience applications. Such systems could be used in combination with the high harmonic generation process as novel, tabletop, high flux X-ray radiation sources providing photon energies up to the keV level. Additionally, strong-field ionization experiments of atom and molecules could help unravel the underlying physics of photo-chemical reactions and molecular transformations. Nevertheless, implementing such sources remains challenging due to the absence of suitable mid-IR laser gain materials. One approach to overcome current limitations is optical parametric chirped pulse amplification (OPCPA). While this method is already commonly used in the visible and near-IR spectral range, just few demonstrations emitting mid-IR, high energy, few-cycle pulses meeting the stringent requirements set by strongfield physics experiments have been demonstrated. In this thesis is present our effort to push the performance of current high power, mid-IR OPCPA systems to overcome existing limitations and to match and even exceed the performance of similar visible and near-IR radiation sources.

We report on the design and implementation of a high efficiency, frequency up-conversion extension of the one-of-a-kind, high power, few-cycle, mid-IR OPCPA system located in the AUO group at the Institute of Photonic Sciences in Barcelona. The unique multi-color source provides optically synchronized, high energy, femtosecond outputs at wavelength ranging from the deep-UV up to the mid-IR regime and a high pulse repetition rate beyond 100 kHz. The short output pulse durations in combination with the all-optical synchronization scheme makes the source a unique tool to drive highly nonlinear and strong-field pump-probe experiments in the tunnel or multi-photon ionization regime.

In the second part, is reported the fundamental redesign and rebuild of the original high power, mid-IR source yielding the first implementation of a GW-level peak-power, mid-IR OPCPA system featuring simultaneously pulse repetition rates beyond 100 kHz. The upscaling of the pulse energy by a factor of 6 while maintaining the pulse repetition rate yields a mid-IR output average power of 19 W. In order to enable such high mid-IR average power, we performed an in-depth study of common, nonlinear mid-IR crystals in respect to their thermal, via residual absorption induced parametric amplification limitations.

In the third part, is presented one of the first realizations of few-cycle, mid- IR pulse self-compression via filamentary propagation in the anomalous dispersion regime in a bulk medium. The spectro-temporal behavior of the self-compressed pulses is studied as a function of the driving mid-IR pulse parameters resulting in temporal pulse shortening down to sub-3 optical cycles. We prove the suitability of this technique as compact and stable post-compression method featuring CEP-stable, few-cycle pulse generation in the mid-IR spectral range.

Thesis Committee
  • Dr Michael Hemmer, Center for Free-Electron Laser Science – Hamburg
  • Prof David Artigas, ICFO PhD Program Coordinator, Prof of Signal Theory and Communications at UPC
  • Prof Philipp Russell, Max-Planck Institute for the Science of Light