Highly efficient soft x-ray spectrometer for transient absorption spectroscopy with broadband table-top high harmonic...

Area of Science:

• Spectroscopy
• X-ray Optics
• Physical Chemistry

Background:

• Ultrafast absorption spectroscopy requires high-performance soft x-ray instruments.
• Conventional spectrometers using gratings have limited efficiency (around 3%).
• Table-top femtosecond high-order harmonic (HOH) sources offer new possibilities for spectroscopy.

Purpose of the Study:

• To develop a novel soft x-ray spectrometer for ultrafast absorption spectroscopy.
• To improve the efficiency and performance compared to existing commercial spectrometers.
• To utilize table-top femtosecond high-order harmonic sources for spectroscopy.

Main Methods:

• Designed a spectrometer based on the Hettrick-Underwood design.
• Employed a reflective zone plate as the dispersive element.
• Utilized a table-top femtosecond high-order harmonic source.

Main Results:

• Achieved an improved efficiency of 12% at the Nitrogen K-edge.
• Obtained a resolving power of 890.
• Demonstrated performance by measuring nitrogen K-edge absorption spectra of calcium nitrate in aqueous solution.

Conclusions:

• The novel soft x-ray spectrometer demonstrates significantly higher efficiency and resolving power.
• The instrument is suitable for ultrafast absorption spectroscopy using table-top HOH sources.
• The results are comparable to measurements performed at large-scale synchrotron facilities.