Probing filamentation dynamics with strong field processes

• Applicant: Professor Dr. Milutin Kovacev
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2014 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 253900879

• Final Report Year: 2019

Final Report Abstract

The goal of the present project was the investigation of femtosecond laser filamentation dynamics using strong field physics processes. This allows to probe propagation dynamics on time scales reaching the attosecond regime. The proposed methodology uses non-perturbative effects like high order harmonic generation (HHG) as a highly sensitive local probe of the intensity of self-guided laser beams. This approach allows for macroscopic and microscopic analysis of fundamental processes of the nonlinear interaction of femtosecond laser pulses with matter. We showed the application of high harmonic spectroscopy to monitor not only the spectral or temporal evolution of the field, but also of self-steepening and intensity dynamics. Concerning the topic of few-cycle dynamics a new type of d-scan scheme employing cross-polarized wave (XPW) generation was proposed. Moreover, the first phase matching study for the generated harmonic radiation in a filament was conducted. A possible application of amplification of harmonic generation was studied and the influence of a preionized targed onto the harmonic generation process was observed. The interpretation and analysis of the experiments are ongoing in order to better understand the filamentation dynamics before the final publication of the results.

Publications

• "Direct observation of pulse dynamics and self-compression along a femtosecond filament", Optics Express 22, (19) 22905-22916 (2014)
  M. Kretschmar, C. Brée, T. Nagy, A. Demircan, H. G. Kurz, U. Morgner, M. Kovačev
  
• "Direct observation of pulse dynamics, influencing high-order harmonic emission along a filament", Conference on Lasers and Electro-Optics (CLEO) - Laser Science to Photonic Applications (2014) ), paper STh1E.1
  M. Kretschmar, T. Nagy, A. Demircan, C. Brée, M. Hofmann, H. G. Kurz, U. Morgner, M. Kovacev
  
• “Impact of spatial inhomogeneities on on-axis pulse reconstruction in femtosecond filaments”, Journal of Physics B: Atomic, Molecular and Optical Physics 48, (9) 094002 (2015)
  C. Brée, M. Kretschmar, T. Nagy, H. G. Kurz, U. Morgner, M. Kovačev
  
• “Few-cycle optical pulse characterization via crosspolarized wave generation dispersion scan technique”, Optics Letters 41, (22) 5246-5249 (2016)
  Ayhan Tajalli, Bruno Chanteau, Martin Kretschmar, Heiko G Kurz, David Zuber, Milutin Kovačev, Uwe Morgner, Tamas Nagy