Zig-zag active-mirror laser with cryogenic Yb3+:YAG/YAG composite ceramics

High-power laser systems require efficient amplification methods to reach desired output levels. Traditional laser configurations often face limitations in thermal management and scalability. Cryogenic cooling has been explored to enhance laser performance by reducing thermal effects. Prior research has demonstrated that low-temperature operation can improve beam quality and efficiency in solid-state lasers. However, achieving high output power while maintaining compactness remains a challenge. The zig-zag optical path has been proposed as a way to increase interaction length without extending the laser cavity. Composite ceramic materials have been used to combine multiple laser components into a single unit. Despite these advances, no prior work had resolved the integration of cryogenic Yb:YAG with zig-zag optics in a scalable format. This gap motivated the exploration of a novel amplifier design using composite ceramics and cryogenic conditions.

The goal of this work was to develop a high-power laser system using a novel amplifier configuration. The researchers aimed to combine zig-zag optical path geometry with cryogenic Yb:YAG Total-Reflection Active-Mirror (TRAM) technology. They sought to demonstrate that this approach could achieve high output power with low pump intensity. The study focused on the feasibility of using composite ceramic materials to house multiple TRAMs in series. Researchers also aimed to evaluate the system's efficiency and scalability potential. The motivation stemmed from the need for compact, high-efficiency laser systems in industrial and scientific applications. By integrating cryogenic cooling with zig-zag optics, the team hoped to overcome thermal limitations. The study aimed to provide a foundation for future high-power laser designs.

The researchers designed a laser system using a zig-zag optical path and cryogenic Yb:YAG TRAMs. They fabricated a compact composite ceramic material containing three TRAMs arranged in series. The system was cooled to cryogenic temperatures to reduce thermal effects. Pumping was achieved using a low-intensity source to evaluate efficiency. Output power and slope efficiency were measured under continuous-wave (CW) operation. The optical path was optimized to maximize interaction length without increasing cavity size. The team tested the system at pump intensities below 170 W/cm² to assess performance. Results were analyzed to determine scalability potential and system limitations.

The system achieved a maximum output power of 214 W under continuous-wave operation. Slope efficiency reached 63% at pump intensities below 170 W/cm². These results suggest that the design is highly efficient even at low pump levels. The use of three TRAMs in series contributed to increased output power. Cryogenic cooling played a key role in maintaining performance stability. The zig-zag optical path allowed for efficient energy transfer without cavity expansion. The compact composite ceramic structure supported the integration of multiple TRAMs. These findings indicate that further scaling could reach output powers exceeding 10 kW.

The authors suggest that the zig-zag active-mirror laser with cryogenic Yb:YAG composite ceramics is a promising approach for high-power laser systems. The design demonstrated output powers of 214 W with a slope efficiency of 63%. The use of cryogenic cooling and zig-zag optics appears to enhance performance. The composite ceramic structure enabled the integration of three TRAMs in series. The system operated efficiently at low pump intensities, suggesting scalability potential. The results may support future efforts to achieve 10 kW output. The authors propose that further optimization could improve beam quality and thermal management. This configuration may serve as a foundation for next-generation high-power lasers.