Brilliant attosecond {\gamma}-ray emission and high-yield positron production from intense laser-irradiated Nano-Micro array

TL;DR

This paper proposes a novel scheme using Nano-Micro arrays and ultra-intense lasers to generate brilliant attosecond gamma-ray bursts and high-yield positron bunches with high efficiency, scalable with laser intensity, and suitable for advanced nuclear and high-energy-density physics research.

Contribution

It introduces a new NMA-based scheme for efficient gamma-ray and positron production, demonstrating high conversion efficiencies and scalability with laser intensity, and explores optimization strategies for particle generation.

Findings

27% of laser energy transferred to gamma-rays at I_0=8×10^{23} W/cm^2

Positron yield of 1.48×10^{11} particles with high density (~10^{22} cm^{-3})

Gamma-ray burst duration of ~440 attoseconds and brilliance of 10^{24} photons s^{-1} mm^{-2} mrad^{-2} per 0.1%BW

Abstract

We investigate a novel scheme for brilliant attosecond {\gamma}-ray emission and high-yield positron production, which is accomplished with an ultra-intense laser pulse incident upon a Nano-Micro array (NMA) with substrate incorporated. This scheme is able to realize effectively electron acceleration and colliding geometry. Both the {\gamma}-ray flash and positron bunch are then generated with high conversion efficiency. At laser intensity of I_0 = 8 times 10^{23} W/cm^2, ~27% of the laser energy is transferred successfully into the {\gamma}-rays, and ~0.7% of the laser energy into the positrons. As a consequence, ultra-short (~440 as) and ultra-brilliant (~10^{24} photons s^{-1} mm^{-2} mrad^{-2} per 0.1%BW @ 15 MeV) {\gamma}-ray burst, and high-yield (1.48 times 10^{11}) and overdense (~10^{22} cm^{-3}) positron bunch are generated. We found a sub-linear scaling of laser-to-photon conversion efficiency (proportional to I_0^{0.75}) and a super-linear scaling of laser-to-positron conversion efficiency (proportional to I_0^{2.5}) with the laser intensity. Multi-dimensional particle-in-cell simulations show that particle ({\gamma} photon and positron) generation can be manipulated by laser-focusing position, and NMA's length and spacing. Optimal conditions for particle generation in NMAs are obtained, indicating that microwire array has the advantage over nanowire array in particle generation in the extreme laser fields. Furthermore, positron annihilation effect in high-energy-density (HED) environment is discussed. The scheme using NMAs would provide effective avenues toward investigating attosecond nuclear science and HED physics with the coming 10 PW laser facilities.