MRI: Development of a High-Power Adaptive Phased Fiber-Array Laser System

目前用于各种行业（汽车、航空航天、国防、核能和聚变能、天然气/石油等）的高功率激光系统。缺乏对高功率激光束特性灵活/智能控制。它们使用千瓦级激光功率的蛮力来熔化或蒸发材料，而无需实时过程监控和智能反馈控制。随着对加工和连接各种新型材料类型的需求不断增加以及增材制造技术的不断发展，高功率激光能量源技术必须满足更严格的拟合-形状-功能要求，以实现出色的光束质量和精确的能流时空控制。该项目的重点是开发一种高能量连续波（CW）自适应相控阵光纤阵列（APFA）激光系统，旨在满足这些要求，从而为激光材料加工的重大进步带来尚未探索的机会。 在各种定向能量应用中，也需要具有优异光束质量和自适应光束控制能力的多千瓦功率激光系统，例如长距离电池充电和光学功率传输、污染区域基础设施元件的远程拆除、未来航天器的光子辅助推进、APFA激光仪器是近年来在高功率光纤激光器和自适应光束控制方面取得技术突破的产物，包括：（a）由七通道高功率光纤放大器系统组成的多kW CW激光能量源，（B）具有先进水冷却系统的高功率自适应光纤阵列激光头，（c）用于自适应减轻由激光束与材料相互作用引起的机械抖动和光学像差的集成传感器，以及（d）混合（反馈/可编程）控制系统，用于高功率能量通量空间和时间特性的实时操纵。所提出的仪器将激光材料加工和定向能量应用中最高度期望的特性和能力结合在一个新颖的单一激光能量源中，包括：优秀（M^21.15）10 kW功率水平下的光束质量，精确（亚微米精度）电子束指向和稳定，大范围焦点转向和自适应重新聚焦，对机械抖动和热诱导像差的自适应补偿、激光束偏振的可编程控制、空间和时间相干性以及能通量空间分布的智能控制。APFA激光能源将大大拓宽研究，并为光纤激光技术、激光材料加工和制造以及先进控制等新兴领域的教育和培训提供绝佳机会，从而增强这些多个科学领域的职业生涯。新激光系统对工业研究人员和大学项目的可用性也有助于当地经济向高科技产业过渡。

The high-power laser systems currently used in various industries (automotive, aerospace, defense, nuclear and fusion energy, gas/oil, etc.) suffer from a lack of agile/intelligent control of high-power laser beam characteristics. They use the brute force of kW-class laser power to melt or evaporate materials without real-time process monitoring and intelligent feedback control. With the increasing demand for processing and joining a variety of novel material types and emerging development of additive manufacturing techniques, the high-power laser energy source technology must meet stricter fit-form-function requirements for excellent beam quality and precise spatial and temporal control of energy flux. This project is focused on development of a high-energy continuous wave (CW) Adaptive Phased Fiber-Array (APFA) laser system that is designed to fulfill these requirements, leading to yet unexplored opportunities for significant advances in laser material processing. Multi-kW power laser systems with excellent beam quality and adaptive beam control capabilities are also required in diverse, directed energy applications, such as long-distance battery recharging and optical power transfer, remote demolition of infrastructure elements in a contaminated area, future photon-assisted propulsion of spacecraft, and distant interrogation of asteroids.Emerging from recent technology breakthroughs in high-power fiber-lasers and adaptive beam control, the APFA laser instrument includes: (a) a multi-kW CW laser energy source comprised of a seven-channel high-power fiber amplifier system, (b) a high-power adaptive fiber-array laser head with an advanced water-cooling system, (c) integrated sensors for adaptive mitigation of mechanical jitter and optical aberrations resulting from laser beam interaction with the material, and (d) a hybrid (feedback/programmable) control system for real-time manipulation of the high-power energy flux spatial and temporal characteristics. The proposed instrumentation combines in a novel single laser energy source the most highly desired characteristics and capabilities in laser material processing and directed energy applications including: excellent (M^21.15) beam quality at 10 kW power level, precise (submicron accuracy) electronic beam pointing and stabilization, wide-range focal spot steering and adaptive refocusing, adaptive compensation for mechanical jitter and heat-induced aberrations, programmable control of laser beam polarization, spatial and temporal coherence, and intelligent control of energy flux spatial distribution. The APFA laser energy source will substantially broaden research and provide an excellent opportunity for education and training in the burgeoning areas of fiber-laser technology, laser material processing and manufacturing, and advanced control, enhancing careers in these multiple scientific fields. The availability of the new laser system to both industrial researchers and University programs also helps the local area economy in its transitioning to high-tech industry.