Observation of Seeded Mn Kβ Stimulated X-Ray Emission Using Two-Color X-Ray Free-Electron Laser Pulses

Area of Science:

• Atomic and Molecular Physics
• X-ray Spectroscopy
• Materials Science

Background:

• Kβ x-ray emission spectroscopy analyzes 3d transition metal electronic structure and dynamics.
• Enhancing specific spectral regions increases sensitivity for new insights.
• Previous work demonstrated Kα amplified spontaneous x-ray emission from Mn solutions.

Purpose of the Study:

• To develop a mechanism for outcompeting dominant Kα amplification for weaker Kβ emission lines.
• To apply amplified emission techniques to chemically sensitive Kβ x-ray spectra.
• To enhance and control the emission of selected final states in the Kβ spectrum.

Main Methods:

• Utilized a two-color x-ray free-electron laser (XFEL) approach.
• One XFEL pulse created the 1s core-hole population inversion.
• A second XFEL pulse seeded the amplified Kβ x-ray emission from a NaMnO4 solution.

Main Results:

• Observed seeded amplified Kβ x-ray emission from a NaMnO4 solution.
• Achieved a signal enhancement of more than 10^5 compared to conventional Kβ emission.
• Demonstrated a method to selectively enhance Kβ emission lines.

Conclusions:

• This study reports the first observation of seeded amplified Kβ x-ray emission.
• The findings represent a significant step towards enhancing and controlling Kβ emission.
• The technique has potential applications in chemical and materials science analysis.