About

A snapshot of the NSF NeXUS Facility at Ohio State

What are the major goals of the project?

This NSF project will develop and commission the National eXtreme Ultrafast Science (NeXUS) Facility. This is a user facility with a peer-evaluated process for obtaining use time, guest offices, a user control room, staff support, and—at its core—the NeXUS System.

The NeXUS System is under development now. It is planned to be a first-of-its-kind combination of a laser driving the generation of extreme ultraviolet (XUV) and soft x-ray pulses with durations from femtoseconds to attoseconds. The laser and XUV pulses are then coupled to multiple experimental end stations that directly support user experiments. The diagram and details below specify the design targets for the NeXUS System.

The NeXUS System


The NeXUS facility will achieve XUV pulse generation and propagation with the combination of five subsystems:

[Subsystem A ]

NeXUS Laser – Generates ultrafast, near-infrared laser pulses at a repetition rate from 100 kHz to several MHz with an average optical power up to 1 kW. Optical pulses are split and used for high harmonic generation, second harmonic generation, third harmonic generation, and/or OPA wavelength tuning.


[Subsystem B ]

Time-Resolved XAS/XRS Beamline – This beamline generates extreme ultraviolet (XUV)/soft x-ray ultrashort pulses with a time resolution below 10 fs, a high repetition rate matching the laser, and a high photon flux to support studies of low cross-section systems.

Time-Resolved Laser Induced Electron Diffraction/Attosecond (TR-LIED/ATTO) End Station – This end station operates in two modes, both capable of time resolving the angular momentum distribution of gas-phase molecules probed by intense infrared pulses and/or XUV attosecond pulses. In one mode, this enables precise spatial-temporal probing of molecular dynamics using re-scattering physics, hence creating molecular movies with sub-femtosecond time resolution and sub-angstrom spatial resolution. In the second mode, XUV pulses probe the faster time scale of the electron dynamics using photoionization attosecond metrology.


[Subsystem C ]

Time-Resolved XAS/XRS Beamline – This beamline generates extreme ultraviolet (XUV)/soft x-ray ultrashort pulses with a time resolution below 10 fs, a high repetition rate matching the laser, and a high photon flux to support studies of low cross-section systems.

Time-Resolved X-Ray Absorption/Reflection Spectroscopy (TR-XAS/XRS) End Station – This end station enables ultrafast spectroscopy of electron dynamics in molecules and materials. It opens the door to XUV studies of photochemical dynamics at time scales necessary to understand and control charge and spin transport during photochemical energy conversion. This end station can also be used with either of two add-ons.

Time-Resolved X-ray Magnetic Circular Dichroism (TR-XMCD) Add-On – This add-on employs a circularly polarized, broadband XUV pulse to measure element-specific magnetization dynamics with attosecond time resolution. This add-on will be utilized to understand photoinduced magnetization switching for applications in ultrafast data processing.

Liquid Sheet Add-on – This add-on generates a free-flowing, ultrathin liquid sheet to support the study of chemical dynamics in solution.


[Subsystem D ]

Time-Resolved ARPES Beamline – This beamline generates extreme ultraviolet (XUV) pulses at the repetition rate of the laser and with a spectral resolution below 30 meV.

Time- and Angle-Resolved Photoemission Spectroscopy (TR-ARPES) End Station – This end station enables time- and angle-resolved photoemission measurements to investigate dynamic processes in materials including electron relaxation, spin relaxation, evolution of spin-momentum locked states, and dynamics of correlated states.


[Subsystem E ]

Time-Resolved STM Beamline – This beamline generates tunable extreme ultraviolet (XUV)/soft x-ray pulses at a time resolution below 500 fs.

Time-Resolved Scanning Tunneling Microscopy (TR-STM) End Station – This end station couples tunable XUV light to an STM in order to combine element-specific spectroscopic contrast with ultrafast time resolution and atomic-scale spatial resolution. This enables studies of temporally and spatially resolved charge and spin dynamics at surfaces.