X-ray speckle visibility spectroscopy in the single-photon limit

Area of Science:

• Physics
• Materials Science
• Spectroscopy

Background:

• Coherent X-ray scattering is a powerful tool for studying material dynamics.
• Traditional methods often require longer exposure times, limiting the study of fast processes.

Purpose of the Study:

• To develop and validate a novel speckle visibility spectroscopy technique for measuring dynamics using coherent X-ray scattering.
• To extend the capabilities of area-detector-based coherent scattering methods to probe faster dynamics.

Main Methods:

• Employed speckle visibility spectroscopy with coherent X-ray scattering.
• Utilized a resonant shutter for exposure times as short as 2 milliseconds.
• Developed an analysis based on the spatial correlation function of individual photon charge droplets for weak scattering data.

Main Results:

• Established a relationship between X-ray contrast in single exposures and the relaxation time of the intermediate scattering function.
• Successfully applied the methodology to measure the diffusion of 72 nm latex spheres in glycerol.
• Demonstrated good agreement between experimental data and theoretical predictions.

Conclusions:

• The developed speckle visibility spectroscopy technique enables the measurement of faster dynamics than previously possible with coherent X-ray scattering.
• This advancement holds significant promise for extending the application of area-detector-based scattering methods.
• The technique offers a new avenue for characterizing dynamic processes in various materials.