High-Average Power, High-Energy, 2-um Laser Source for High-Harmonic Generation

Laser-driven, tabletop X-ray sources based on high harmonic generation provide unique tools with unprecedented temporal and spatial resolution for application in material science, condensed matter physics, biology, and medicine. Also such tabletop X-ray sources are much more compact and cost- efficient as compared to currently used synchrotrons and free-electron lasers. Development of next- generation, laser-driven X-ray sources is critically dependent on power scaling of high-intensity, mid- IR stages driving the high harmonic generation. Proposed development of a high-pulse-energy, high-repetition-rate, picosecond-scale, 2-m, Holmium-laser technology will enable the power scaling of high-intensity, mid-IR laser drivers and, in turn, X-ray power output. The laser system will be based on a modular, all-amplifier architecture utilizing a mode-locked seed oscillator and robust, high-power, Ho:YLF solid-state amplifier modules to scale the output up to 100 mJ at ~kHz repetition rates. Phase I effort confirmed the feasibility of the proposed approach. A Ho:YLF regenerative amplifier allowed scaling the energy of picosecond-scale pulses up to 2 mJ at 1-kHz rate, exceeding the original target. Initial experiments with single-pass Ho:YLF power amplifier demonstrated further scaling to 7-mJ pulse energy. The main objective of the Phase II program is to design and build a ruggedized, modular, chirped-pulse-amplification, Ho:YLF laser system based on regenerative amplifier module and a set of single-pass amplifiers with the goal of scaling the pulse energy up to 100 mJ at kHz-rate. As the final effort a complete packaged system will be built and delivered to DoE customer. Commercial Applications and Other Benefits: The primary application of the proposed laser technology is as a pump source for ultra-high-intensity mid-IR lasers which drive X-ray sources based on high-harmonic generation (HHG). There is a growing interest in applying HHG laser technology for industrial applications due to access to particular X-ray wavelengths and relative compactness of the tabletop HHG systems. Additional applications include terahertz generation, and remote sensing and eye-safe, long-range lidar/ladar with high spatial resolution at 2-m wavelength.