Industry Partnership Eyes High-Performance Diode Laser Stacks

The Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH) has partnered with TRUMPF, LayTec, and Finetech to develop high-power diode laser stacks with high duty cycle and optical power, and low fabrication cost. The work is to take place under the HOTSTACK project, coordinated by TRUMPF. The initiative addresses the need for stacked arrays of diode lasers to pump the new generation of pulsed solid-state lasers of the highest energy class.

Diode lasers are needed in high volumes for these systems, but manufacturing processes, such as epitaxial growth, III-V wafer structuring, and etching processes are complex. Meanwhile, reliable process control is essential for understanding and controlling the manufacturing process.

A collaboration between TRUMPF, The Ferdinand-Braun-Institut, LayTec, and Finetec will develop high-power diode laser stacks with high duty cycle and optical power, and low fabrication cost. Courtesy of EuPRAXIA.

LayTec, in collaboration with FBH, will develop integrated optical analysis techniques for both III-V epitaxial growth and wafer process technology. The techniques are intended to improve process understanding and control for such structures. The control methods target greatly increased diode laser fabrication yield, and are therefore anticipated to directly enable a highly-cost-effective diode laser fabrication to support large high energy laser systems.

The full project will realize two types of high-power diode laser stack(s) research prototypes. The development of industrial design stacks, or Type 1, targets the emerging secondary source industry. This portion of the project will yield a cost-effective industrial design, the partners said. Specifically, project partner TRUMPF aims to increase the average pump power per stack by a factor of around 20, compared to current systems, via a higher pulse repetition frequency and higher optical pulse power. Parallel research efforts by project partner Finetech, which examines new die bonding technologies and production automation, should also drastically reduce manufacturing costs.

The Type 2 stacks developed by the collaborators will support research into the next generation of the highest energy laser systems, such as those required for the EuPRAXIA plasma-based accelerator facility. The aim is to increase the average pump power by a factor of 100. The work on this will mainly take place at the Ferdinand-Braun-Institut.

HOTSTACK is a ProFIT Innovation project co-financed between 2023 and 2025 with funds from the European Fund for Regional Development (ERDF) Berlin.