Electron Acceleration by Relativistic Surface Plasmons in Laser-Grating Interaction

Area of Science:

• Plasma physics
• Laser-matter interaction
• Surface plasmonics

Background:

• Investigating energetic electron bunch generation is crucial for developing advanced light sources.
• Understanding laser-plasma interactions at ultrahigh intensities informs novel acceleration techniques.

Purpose of the Study:

• To investigate energetic electron bunch generation using ultraintense laser pulses on grating targets.
• To explore the role of surface plasmons in laser-driven electron acceleration.

Main Methods:

• Utilized short, ultraintense laser pulses (I>10^19 W/cm^2) with ultrahigh contrast (10^12) on grating targets.
• Performed experiments at incidence angles near the resonant condition for surface plasmon excitation.
• Employed three-dimensional particle-in-cell simulations to model the interaction and electron acceleration.

Main Results:

• Observed strong electron emission in a narrow cone along the target surface, with energies peaking at 5-8 MeV and total charge ~100 pC.
• Demonstrated significant enhancement in both energy and number of emitted electrons compared to flat targets.
• Simulations confirmed the generation of relativistic surface plasmons driving the acceleration process.

Conclusions:

• Grating targets significantly enhance laser-driven electron bunch generation via surface plasmon excitation.
• This scheme offers a promising pathway for compact, ultrashort sources of MeV electrons.
• The findings advance the field of high-field plasmonics and laser-driven particle acceleration.