X rays from microstructured targets heated by femtosecond lasers.

Area of Science:

• Plasma Physics
• X-ray Generation
• Laser-Matter Interaction

Background:

• Efficient conversion of laser energy to X-rays is crucial for scientific research and applications.
• Traditional methods using flat targets have limitations in X-ray yield.
• Microstructured surfaces offer potential for enhanced laser-plasma interactions.

Purpose of the Study:

• To demonstrate efficient conversion of ultrashort-pulse laser energy to X-rays above 1 keV.
• To investigate the effectiveness of various microstructured surfaces for X-ray generation.
• To compare the X-ray yield from microstructured targets with conventional flat targets.

Main Methods:

• Generation of laser-produced plasmas on microstructured surfaces using ultrashort laser pulses.
• Utilized lithographically produced grating targets, porous gold, and porous aluminum targets.
• Characterization of emitted X-ray energies and spectra.

Main Results:

• Achieved X-ray energies above 1 keV.
• Lithographic grating targets produced 0.1 mJ of kilo-electron-volt X-rays.
• Porous gold and aluminum targets emitted 1 mJ of X-rays, a 100-fold improvement over flat targets.
• The K-shell emission spectrum of porous aluminum was dominated by heliumlike spectral lines.

Conclusions:

• Microstructured surfaces significantly enhance the efficiency of ultrashort-pulse laser energy conversion to X-rays.
• Porous metallic targets demonstrate superior performance for generating high-energy X-rays.
• The findings pave the way for more efficient X-ray sources for scientific and technological applications.