Development of new technologies to scale the average power (pulse energy and pulse rate) and efficiency of high average power DPSSL

世界上最强大的多焦耳二极管泵浦固态激光器（DPSSL）DiPOLE 100由STFC内的中央激光设施（CLF）开发[1]，最近已证明在10 Hz（1.5 kW）的脉冲速率下将10 ns脉冲放大到150 J，光-光效率为30% [2]。双极气冷多板条放大器技术是CLF目前为极端光子学和应用中心（EPAC）开发的10 Hz拍瓦激光器的组成部分。偶极技术用于最终高能量Ti：Sa放大器的泵浦激光器（频率转换为绿色后）和Ti：Sa放大器本身[3]。在国家点火设施[4]最近的点火演示之后，对DPSSL系统的进一步能量和效率缩放的兴趣增加了。此外，下一代激光驱动等离子体加速器将需要在提高的效率和脉冲重复率下的高脉冲能量操作（kHz制度）[5]。该项目的重点是通过研究新技术来推动当前偶极系统的边界，通过将脉冲速率增加到1 kHz和脉冲能量超过150 J来扩展平均功率超过千瓦级。学生将致力于建模，作为EPAC升级路径的一部分，设计、测试和表征新的100 Hz DiPOLE系统。他们将探索新的泵浦方案和替代放大器的几何形状，以提高效率，同时改善诊断和光束校正技术，以保持光束质量。还将研究替代增益介质和热管理解决方案，以进一步扩展能量和脉冲率。最后，学生将评估这项技术在基于激光的惯性约束聚变和激光驱动等离子体加速器应用中的未来。

The world's most powerful multi-Joule, diode-pumped solid-state laser (DPSSL), DiPOLE100, was developed by the Central Laser Facility (CLF) within STFC [1] and has recently demonstrated amplification of 10 ns pulses to 150 J at a pulse rate of 10 Hz (1.5 kW) with an optical-to-optical efficiency of 30% [2]. DiPOLE gas cooled multi-slab amplifier technology is integral to the 10 Hz petawatt laser currently being developed by the CLF for the Extreme Photonics and Applications Centre (EPAC). DiPOLE technology is utilised in both the pump laser for the final high energy Ti:Sa amplifier (after frequency conversion into the green) and for the Ti:Sa amplifier itself [3]. Interest in further energy and efficiency scaling of DPSSL systems has increased following the recent demonstration of ignition at the National Ignition Facility [4]. Furthermore, next generation laser-driven plasma accelerators will require high pulse energy operation at increased efficiency and pulse repetition rate (kHz regime) [5].This project focuses on pushing the boundaries of current DiPOLE systems by investigating new technologies required to scale average power beyond the kilowatt level by increasing pulse rate towards 1 kHz and pulse energies beyond 150 J. The student will work on modelling, design, testing and characterisation of new 100 Hz DiPOLE systems, as part of the upgrade path for EPAC. They will explore novel pumping schemes and alternative amplifier geometries to improve efficiency, whilst improving diagnostics and beam correction techniques for maintaining beam quality. Research into alternative gain media and thermal management solutions to scale energy and pulse rate further will also be undertaken. Finally, the student will evaluate the future of this technology for laser-based inertial confinement fusion and laser-driven plasma accelerator applications.