MRI: Acquisition of a High-Power 2-um Laser System as the Backbone of an Utrafast X-Ray/THz Facility

This project, Acquiring a High-peak-power High-repetition-rate Ultrafast Infrared Laser System at 2 µm Wavelength, provides the backbone of a multi-user facility named, "User Facility for Attosecond Soft x-rays and Terahertz (UFAST)". With the highest average power of its kind anywhere in the world today, this laser system will enable a tabletop attosecond (a billionth of a billionth of a second) soft-x-ray photon source at record high flux with sufficient photon energies for directly exciting, at the deepest level, essential atoms, such as carbon, nitrogen, and oxygen, and also enable long-wavelength-infrared and terahertz sources of high-field and few – single cycle pulse duration.

These photon sources and the pump laser will be utilized to carry out frontier research projects where facility users develop the world’s fastest x-ray photon source, track electron motion at its natural time scale with atomic spatial resolution, monitor quantum/topological phase transition dynamics, investigate new photo-induced physical and chemical processes in materials, test a new theory for a novel cold-nanoplasma source, and further improve a terahertz spectroscopic tool for probing uncharted regions of the universe. Results of these research projects will advance knowledge and technologies in physical, chemical, and planetary sciences, as well as optical engineering.

UFAST delivers unique parameters that are not available around the world and will enhance US competitiveness in high-flux ultrafast technologies and attosecond science. The engineering and research activities at UFAST will grant graduate and undergraduate students, as well as postdoctoral scholars, access to frontier ultrafast research and technologies, and particularly promote training of minority students in cutting-edge research projects.

The future generation of work force will be trained in the construction and operation of a unique facility involving advanced photon sources and detectors, and will obtain research, teamwork, and leadership skills. In addition to the multidisciplinary nature of its applications, the facility will be accessible to users across the US and from around the world and will stimulate collaborations across research fields and institutions, as well as between experimentalists and theorists.

The laser system to be acquired will deliver 2-µm-wavelength and few-cycle-duration pulses with carrier envelope phase (CEP) stabilization at a repetition rate of 100 kHz. It will be used to pump a table-top photon source of isolated attosecond pulses in the extreme ultraviolet (XUV) and water window (284 – 543 eV) range, and to pump photon sources of few – single-cycle pulses in the long wavelength infrared (8 – 15 m) and terahertz (0.6 – 60 THz) range.

This new capability will enable research advances in several areas: time-resolved investigation of processes driven by or involving electronic dynamics, such as electron correlation, charge migration and transfer, in gas and condensed phase targets, quantum and topological systems as well as at surfaces; investigation of strong-field phenomena, particularly the intensity-demanding quasistatic regime, in solids over a variety of laser parameters; investigation of new optical breakdown mechanisms and optimization of laser machining quality; experimentally demonstrating photon-induced low-temperature non-equilibrium nanoplasmas; and extending laboratory spectral library with terahertz time-domain spectroscopy to fill a knowledge gap regarding the composition and evolution of the solar system.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.