Coherent Optical Signatures of Electron Microbunching in Laser-Driven Plasma Accelerators.

Area of Science:

• Plasma physics
• Accelerator physics
• Beam dynamics

Background:

• Laser-driven plasma accelerators are a promising technology for generating high-quality electron beams.
• Characterizing the properties of microbunched electron beams is crucial for their application in advanced light sources and accelerators.

Purpose of the Study:

• To investigate the properties of microbunched electron beams produced by a laser-driven plasma accelerator.
• To measure the divergence and radius of the microbunched electron beam using coherent optical transition radiation interferometry (COTRI).

Main Methods:

• Utilized coherent optical transition radiation interferometry (COTRI) to analyze electron beams.
• Employed a COTRI model to deduce the divergence of the microbunched electron population.
• Analyzed coherent optical transition radiation (COTR) images to determine the microbunched beam radius.

Main Results:

• The divergence of the microbunched electron beam was found to be approximately 9 times smaller than the ensemble beam divergence (∼3 mrad).
• The radius of the microbunched beam was measured to be less than 3 μm.
• The estimated transverse normalized emittance of the microbunched electron distribution was found to be approximately 0.4 mm mrad.

Conclusions:

• Microbunching in laser-driven plasma accelerators can lead to significantly reduced electron beam divergence and radius.
• The achieved low emittance demonstrates the potential of this technique for generating high-quality electron beams for advanced applications.
• COTRI is an effective method for characterizing the properties of microbunched electron beams from plasma accelerators.