Single crystal fibers as a laser gain medium : study of the pump beam propagation and consequences on laser systems

Power and energy scaling of pulsed laser is a scientific and technological challenge which motivated a lot of research and development efforts over the last decades. Single crystal fiber (SCF) is a hybrid laser architecture between conventional bulk crystals and optical fibers. It has been developed in collaboration between the Charles Fabry Laboratory near Paris and Fibercryst which is a laser company based in Lyon. Over the last ten years, many different SCF laser systems have been demonstrated such as Q-switched oscillator at different wavelength or ultrafast laser amplifiers.

The first part of the presentation will focus on an overview of the key concepts and experimental results for the SCF technology. The main part of the presentation will focus on the experimental and numerical study of the pump beam propagation in the SCF. It will show how we were able to observe and understand several surprising features of the pump intensity distribution in the SCF. Finally, the role of saturation of absorption and its influence on the effective pump to signal overlap will be discussed.