Promotionsvortrag Physik: „Single-cycle pulse generation at megahertz repetition rates in hollow-core fibres“

Ankündigung des Promotionsvortrags von: Herrn Daniel Schade

Few- or single-cycle laser pulses are crucial in a plethora of scientific applications such as ultrafast spectroscopy and attosecond science. Despite the recent advances in laser technology, the gen-eration of high-peak-power pulses with these durations is still challenging, in particular at mega-hertz repetition rates, and typically requires external nonlinear compression. Gas-filled anti-reso-nant guiding hollow-core photonic crystal fibres (AR-PCFs) are an ideal platform for the compres-sion of μJ-level pulses, due to their low-loss broadband transmission and flexibility to tailor both nonlinearity and dispersion over a wide range.

This talk focuses on the theoretical and experimental explorations conducted in order to advance high-quality pulse compression to even shorter output durations and higher repetition rates. Scal-ing relations for soliton self-compression - a process resulting from nonlinearity in anomalous dis-persion - are investigated and their limits are identified. An optimal parameter region for the non-linear dynamics is marked out to facilitate high-quality pulse compression. By relating it to the fibre and setup design parameters its validity is proven, realising 50-fold compression to 5 fs.

With the introduction of an AR-PCF-based precompression stage even 100-fold compression to 3.8 fs single-cycle duration is achieved at repetition rates up to 10 MHz while ensuring high effi-ciency, pulse quality and a great long- and short-term setup stability. Aiming to increase the rep-etition rate further, fundamental investigations on the main limiting factor, the thermal buildup from the recombination of photoionised electrons, were conducted in order to grasp a deeper under-standing and possible solutions to this challenge..

(Vortrag auf Englisch)

Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.