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^2<1.15) 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.