Einladung zum Promotionsvortrag von Herrn Alexey Ermolov:
„Ultrashort UV pulses via nonlinear light matter interaction in gas-filled hollow-core fibres: generation and characterization“
In this talk I would like to show that gas-filled hollow-core photonic crystal fibre (HC-PCF) can be an efficient source of coherent ultraviolet pulses covering the entire spectral range from 100 nm to 350 nm and having a duration as short as 4 fs. By controlling the gas fillings and the pressure along with the pumping pulse parameters (such as pulse duration and energy) it is possible to reach the regime where solitons are generated in the fibre. Subsequent soliton self-compression down to subfemtosecond duration, partial ionization of a gas in the core and interaction between the soliton and the plasma allows generation of dispersive waves tunable across the vacuum ultraviolet spectral region. The efficiency of the source exceeds 1 % with the vacuum UV pulse energies in excess of 50 nJ. By choosing the optimal set of parameters, a supercontinuum, spanning at least between 115-1000 nm, is generated. Furthermore this source of dispersive waves in the vacuum UV can be used in angle resolved photoemission spectroscopy.
The full temporal and spectral characterization of ultraviolet pulses is essential for many applications. Therefore the design and realization of transient grating cross-correlation frequency resolved optical gating (TG-XFROG) for the characterization of UV dispersive waves is also presented in this talk. A dispersive wave centered at 275 nm is measured to have a duration as short as 4 fs, proving its ultrashort nature. TG-XFROG is also shown to be very broadband and sensitive, potentially allowing for the measurement of the full supercontinuum from deep UV to near IR.
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.