Compact gigawatt-class sub-picosecond Yb:YAG thin-disk regenerative chirped-pulse amplifier with high average power at up to 800 kHz

摘要

Ultrashort pulses are capable of processing practically any material with a negligible heat affected zone [1]. For productive industrial applications a pulse duration of about 5 ps is a well established compromise between being faster than the electron-phonon interaction time of the material and being long enough to suppress detrimental effects such as nonlinear interaction with the ablated plasma plume. The scalable disk technology applied to high peak power lasers has resulted in today's most powerful ultrafast systems for high precision industrial micro processing [2]. However, sub-picosecond pulses can further increase the ablation efficiency for certain materials, depending on the available average power and peak fluence as well as the desired feature size. On the one hand, for practical situations the efficiency generally changes little from 1 ps to 500 fs [3,4]. On the other hand, the situation may be different at harmonic wavelengths, where a careful optimization at high average power is challenging, in particular as frequency conversion is typically optimized for certain pulse durations and energies.