Electron energy analysis by phase-space shaping with THz field cycles

Area of Science:

• Physics
• Materials Science
• Spectroscopy

Background:

• Time-resolved electron energy analysis is crucial for understanding material properties and light-matter dynamics.
• Existing methods face limitations in achieving high resolution and precision.

Purpose of the Study:

• To introduce a novel all-optical concept for measuring femtosecond electron pulse energy spectra.
• To achieve sub-eV resolution in electron energy analysis.

Main Methods:

• Utilizing laser-generated terahertz (THz) radiation to precisely measure arrival time differences within electron pulses.
• Employing controlled dispersion and compression of electron pulses to optimize energy resolution, signal strength, and time resolution.
• Conducting a proof-of-concept experiment using aluminum samples.

Main Results:

• Demonstrated sub-eV energy resolution (<3.5 eV rms) for 70-keV electron pulses over a 0.5 m drift distance.
• Simulations indicate a two-stage scheme can achieve <10 meV resolution.
• The achievable resolution is primarily limited by THz field strength and measurement time.

Conclusions:

• The developed all-optical method offers a significant advancement in femtosecond electron pulse analysis.
• This technique provides a tunable trade-off between energy resolution, signal strength, and time resolution.
• Future applications include detailed studies of ultrafast phenomena in materials and chemical processes.