Free-space transport lines are currently used by DOE to deliver high-power ultrashort pulse laser (USPL) beams from the laser source to the destination of applications. However, free-space transport lines always suffer from laser pointing instability control, optical damages, low transport efficiency, and maintenance difficulty. Most recently, hollow-core fibers filled with dry air, noble gas, or even vacuum have been demonstrated as outstanding transport lines for high-power USPL beam delivery. Leveraging our recent successful fabrication of anti- resonant hollow-core fibers (AR-HCF) and substantial experience in USPLs, NP Photonics proposes to design and develop a polarization-maintaining (PM) AR-HCF-based high-power USPL beam delivery system with high stability, high reliability, high transport efficiency, and automatic coupling capability. In this Phase I program, PM-AR-HCFs at 1-?m will be designed and fabricated, and a high-efficiency and high-reliability beam launching unit with automatic coupling capability will be designed and demonstrated. In Phase II, PM-AR-HCF-based high- power USPL beam delivery systems at 1 ?m and 0.5 ?m, meeting or exceeding the requirements of DOE applications, will be developed and delivered. Dual use applications for the proposed high energy ultrafast lasers include directed energy weapons, material processing, medical applications, and scientific research.
