Thin-disk laser scaling limit due to thermal lens induced misalignment instability

Abstract

We present a fundamental obstacle in power scaling of thin-disk lasers related to self-driven growth of misalignment due to thermal lens effects. This self-driven growth arises from the changes of the optical phase difference at the disk caused by the excursion of the laser eigen-mode from the optical axis. We found a criterion based on a simplified model of this phenomenon, which can be applied to design laser resonators insensitive to this effect. Moreover, we propose several resonator architectures that are not affected by this effect.

Multi-pass resonator design for energy scaling of mode-locked thin-disk lasers

“…This shrinking presently limits energy and power scaling [19] of state-of-the-art thin-disk mode-locked lasers. Another power scaling limitation of thin-disk laser has been recently disclosed [20]. It is related to a self-driven growth of misalignment arising from variations of the thermal lens at the thin-disk caused by the excursion of the laser Eigenmode from the optical axis.…”

“…It is related to a self-driven growth of misalignment arising from variations of the thermal lens at the thin-disk caused by the excursion of the laser Eigenmode from the optical axis. The sensitivity of the 4f-based multi-pass oscillators to this misalignment increases linearly with the number of passes N. On the contrary, multi-pass resonators based on the here presented architecture can be designed to avoid this limitation [20]. Plotted are the cavity Eigen-mode (TEM00-mode) waist w at the thin-disk position for variations of the thin-disk thermal lens from the layout value.…”

Modelling of natural convection in thin-disk lasers

“…In fact, the knowledge of the influence of these parameters on the laser operation is of crucial importance for the design of advanced high-power fundamental-mode thin-disk oscillators [4] and amplifier systems [6,7]. Although a variety of different methods exists to estimate and compensate for thermally induced aberrations [4,[8][9][10][11][12], a complete elimination of aberrations introduced due to natural convection is only possible by operating the whole laser in vacuum [13], which, however, leads to an increased amount of complexity. If this effort is to be avoided, the influence of the convection needs to be considered in detail to be able to optimize the countermeasures.…”

Passive alignment stability and auto-alignment of multipass amplifiers based on Fourier transforms

“…The concept of Fourier-based amplifiers has been introduced in [10] and successively elaborated in [11,12,13,14,9], where a detailed comparison between Fourierbased and state-of-the-art multipass amplifiers based on the 4f-relay imaging is presented. In contrast to these earlier considerations, here another crucial aspect of laser design is considered, namely, the stability of the amplifier performance to misalignments (tilts).…”