Ultra-bright γ-ray emission and dense positron production from two laser-driven colliding foils

Area of Science:

• High-energy physics
• Plasma physics
• Quantum electrodynamics

Background:

• Matter-energy conversion is possible with high-power lasers.
• Producing dense GeV positrons requires extremely high laser intensities (~10^24 Wcm^-2).
• Existing methods face challenges in achieving efficient positron production.

Purpose of the Study:

• To propose an all-optical scheme for ultra-bright gamma-ray emission and dense positron production.
• To achieve efficient particle generation at lower laser intensities (10^22-23 Wcm^-2).
• To explore potential for triggering pair plasma collective effects and laboratory astrophysics.

Main Methods:

• Irradiating two colliding elliptically-polarized lasers onto two diamondlike carbon foils.
• Utilizing laser radiation pressure for electron acceleration.
• Leveraging relativistically induced foil transparency for laser penetration.
• Incorporating quantum electrodynamics in 3D simulations.

Main Results:

• Achieved ultra-bright gamma-photon emission (~10^25 photons/s/mm^2/mrad^2/0.1%BW at 15 MeV).
• Generated a GeV positron beam with a density of 2.5x10^22 cm^-3 and flux of 1.6x10^10/shot.
• Demonstrated efficient Compton back-scattering and particle production at 10^22-23 Wcm^-2 laser intensities.

Conclusions:

• The proposed scheme offers an efficient pathway for dense positron and gamma-ray production.
• This method significantly reduces the required laser intensity compared to previous approaches.
• The findings pave the way for investigating laboratory astrophysics and pair plasma phenomena.