Advancing photonics for ultrafast science and technology

Understanding the interaction of intense ultrashort light pulses with plasmas is a key requirement to advance many ground-breaking strong-field physics applications like high harmonics generation (HHG), attoscience, and lightwave electronics. Gas-filled hollow-core photonic crystal fibers (HC-PCF) have emerged in recent years as an ideal platform for this purpose. The tight confinement of high intensity few-cycle laser pulses over long distances has made it possible to study the coherent nonlinear interaction between light and photo-ionized plasmas in a well-controlled environment, which led to the generation of light with extreme properties both in the temporal and the spectral domain.In this project I propose to explore new regimes of light-plasma interaction by combining advancements in the state-of-the-art of few-cycle laser pulse amplification in optical fibers with new concepts of plasma generation in HC-PCF. Few cycle pulses possess an extremely large spectral bandwidth in the order of one optical octave that exceeds the linear gain-bandwidth of any known medium, making their amplification a challenging task that will be tackled in this project with innovative concepts in fiber-optic technology, which are based on fiber manufacturing technology developed at the University of Bern. The developed amplification systems address the current quest for high average power few-cycle pulse sources, triggered by the need to increase the photon flux for coherent XUV spectroscopy, imaging, and attoscience applications based on HHG, which suffers from low efficiency.Further I envisage to combine these novel sources with new possibilities for exciting in-fiber electric gas discharges in HC-PCF. This would create an innovative and extremely versatile photonic platform ideally suited for the fundamental studies of light-plasma interactions in regimes not currently accessible, and also enable the development of in-fiber gas lasers and other novel light sources in emerging spectral regions with high potential impact on fundamental science, biology, healthcare, and sensing applications.