All-optical tabletop strong-field terahertz pump-Ultrafast x-ray probe platform

Area of Science:

• Condensed Matter Physics
• Materials Science
• Physical Chemistry

Background:

• Ultrafast time-resolved measurements using X-ray probes are crucial for understanding dynamic processes in materials.
• Access to strong-field terahertz (THz) sources and ultrafast X-ray probes has been limited to large-scale facilities.
• A compact, versatile platform is needed to democratize these advanced experimental capabilities.

Purpose of the Study:

• To design and implement a novel, compact, all-optical tabletop platform for strong-field terahertz (THz) pump-ultrafast X-ray probe experiments.
• To achieve efficient generation and precise synchronization of intense THz pump pulses and ultrafast X-ray probe pulses.
• To demonstrate the platform's capability in studying ultrafast phenomena, such as structural phase transitions.

Main Methods:

• Utilized femtosecond laser-driven THz and X-ray sources, optimizing laser pulse chirp for maximum generation efficiency.
• Generated intense THz pump pulses (up to 3 MV/cm, 0.1-3 THz) via optical rectification in organic crystals.
• Produced ultrafast X-ray probe pulses (Cu Kα photons) using intense laser interactions with copper foil targets at 100 Hz repetition rate.
• Achieved spatial and temporal overlap of THz and X-ray pulses using an auxiliary near-infrared laser pulse.

Main Results:

• Successfully implemented a compact, operational platform for strong-field THz pump-ultrafast X-ray probe measurements.
• Demonstrated the platform's capability by performing measurements on the ultrafast structural phase transition of vanadium dioxide.
• The platform enables selective excitation, control, and high-temporal-resolution in situ detection of ultrafast lattice dynamics.

Conclusions:

• The developed all-optical tabletop platform provides unprecedented accessibility to strong-field THz pump-ultrafast X-ray probe spectroscopy.
• This versatile tool facilitates in-depth investigation of ultrafast materials science and non-equilibrium physics.
• The platform opens new avenues for studying dynamic processes in materials with high temporal resolution.