High power Kerr-lens mode-locked thin-disk oscillators

Abstract

Titanium doped sapphire (Ti:sapphire) systems are the backbone of current ultrafast technology and they are invaluable research tools in contemporary science. However, little progress was observed in their average power scaling due to lack of suitable pumping systems, therefore, no Ti:sapphire laser in the kilowatt-class exists. In contrast, ytterbium (Yb) doped gain media is cementing itself as the new-wave of ultrafast technology. Enabled by the diminished costs of high-grade crystal production for industrial applications, maturity of optics and the developments of high power laser diodes able to pump these gain media, Yb-doped solid-state laser are more cost effective, compact and of lower complexity when compared to titanium doped sapphire systems. Not only does this makes them attractive for industrial applications, but their lowered complexity and cost mean that their further dissemination through the scientific world becomes easier, opening the doors to cutting-edge research in every scientific subject. Within this frame, the development aspects of compact high power ultrafast thin-disk laser oscillators based on Yb gain media will be given. Not only about their design and implementation, but also on how to further improve a system by its post-compression and implementing carrier-envelope offset (ϕ CEO ) locking. At the core of this work is the understanding and effective implementation of hard-aperture Kerr-lens mode-locking which enables a successful exploitation of the gain bandwidth offered by these gain media. The work being reported in this thesis aims to deliver several of the important aspects and hurdles which may be encountered while implementing a state-of-the-art high-power system and also provide a groundwork to future developments by the demonstration of two things: first, how to improve existing numerical methods to help with the design of high-power oscillators and second, give a detailed guide towards the ϕ CEO locking of such systems.