Project

The main objective of the project is to demonstrate the feasibility of industrial high-average power ultrafast Ti:sapphire (Ti:Sa) lasers and their excellent qualification for demanding high-productivity precision laser material processing applications. To achieve the targeted high output powers, the  thin-disk (TD) geometry shall be employed, which already enabled the efficient generation of up to 740 W of cw fundamental mode power from one Yb:YAG crystal. Symmetrical double-sided cooling with two transparent diamond heat spreaders shall be used to optimize the cooling of the thin Ti:Sa crystal. Within the project, two ultrafast Ti:Sa TD laser systems, one with chirped pulse amplification (CPA) to obtain high-energy pulses and the other without CPA for high repetition rates, both with a maximum average output power of at least 200 W at a pulse duration of well below 100 fs shall be demonstrated.

The CPA system, comprising a multipass TD amplifier, shall achieve a pulse energy of 10 mJ at 20 kHz repetition rate. The multipass amplifier will be pumped by two nanosecond pulsed frequency-doubled solid-state lasers developed within the project which are operating at 532 nm with an average output power of 300 W each. The high-repetition rate system shall be a high-power TD oscillator with a pulse energy of 20 µJ at about 10 MHz. A commercial cw Yb:YAG TD laser with intracavity frequency doubling emitting about 500 W at 515 nm shall be used as pump source. To demonstrate the excellent qualification of the ultrafast oscillator for fast, ultra-precise micromachining of transparent materials, high-speed cutting of glass will be investigated as high-volume reference application. With the CPA system, which is especially well suited for ultra-precise drilling, the ultra-high aspect ratio percussion and single-shot drilling of transparent substrates shall be investigated.