High average power temporal pulse compression in a Xe-filled Kagome-type hollow-core photonic crystal fiber (HC-PCF)

Various laser technologies deliver picosecond pulses in the range of a few J pulse energy and at MHz repetition rates. Compressing these pulses efficiently down to the femtosecond regime is important for various applications in fundamental science and technology. SPM-induced spectral broadening in a large mode area (LMA) fiber and subsequent temporal compression can produce large compression factors and high efficiencies [1, 2]. However, fiber damage limits the maximum achievable compressed pulse energy to less than 1 J. Even state-of-the-art silica LMA fibers appear not suitable to compress substantially higher pulse energies due to bulk damage and self-focusing, which limits the maximum peak power to 4 MW [3]. One way to overcome these limitations is the use of gas filled HC-PCF, which offer long interaction lengths and small mode areas. Compression of 120-fs pulses to 50-fs at mW average power levels has been demonstrated in a xenon-filled standard photonic band gap (PBG) fiber [4]. In our experiment we used a Kagome-type HC-PCF, for which the field overlap is more than ten times lower [5]. Since the damage threshold scales inversely with the field overlap, guiding of high pulse energies and peak powers becomes feasible.