Isolated Attosecond $\gamma$-Ray Pulse Generation with Transverse Orbital Angular Momentum Using Intense Spatiotemporal Optical Vortex Lasers

TL;DR

This paper demonstrates the generation of isolated attosecond gamma-ray pulses with transverse orbital angular momentum using intense spatiotemporal optical vortex lasers, offering a novel method with improved beam quality and new angular momentum properties.

Contribution

It introduces a new STOV laser-driven technique for producing isolated attosecond gamma-ray pulses with transverse orbital angular momentum, overcoming previous beam divergence issues.

Findings

Generated 300-attosecond gamma-ray pulses with high collimation.

Achieved ultra-brilliant gamma-ray flux of 5×10^{24} photons/s/mm²/mrad²/0.1%BW at 1 MeV.

Demonstrated a method that simplifies beam requirements compared to prior Gaussian-based approaches.

Abstract

An isolated attosecond vortex $\gamma$-ray pulse is generated by using a relativistic spatiotemporal optical vortex (STOV) laser in particle-in-cell simulations. A $\sim$ 300-attosecond electron slice with transverse orbital angular momentum (TOAM) is initially selected and accelerated by the central spatiotemporal singularity of the STOV laser. This slice then collides with the laser's reflected Gaussian-like front from a planar target, initiating nonlinear Compton scattering and resulting in an isolated, attosecond ($\sim$ 300 as), highly collimated ($\sim$ 4$\degree$), ultra-brilliant ($\sim 5\times 10^{24}$ photons/s/mm$^2$/mrad$^2$/0.1\%BW at 1 MeV) $\gamma$-ray pulse. This STOV-driven approach overcomes the significant beam divergence and complex two-laser requirements of prior Gaussian-based methods while introducting TOAM to the attosecond $\gamma$-ray pulse, which opens avenues for ultrafast imaging, nuclear excitation, and detection applications.