Pair production can be triggered by high-intensity lasers via the Breit-Wheeler process. However, the straightforward laser-laser colliding for copious numbers of pair creation requires light ...intensities several orders of magnitude higher than possible with the ongoing laser facilities. Despite the numerous proposed approaches, creating high-energy-density pair plasmas in laboratories is still challenging. Here we present an all-optical scheme for overdense pair production by two counter-propagating lasers irradiating near-critical-density plasmas at only ∼10
W cm
. In this scheme, bright γ-rays are generated by radiation-trapped electrons oscillating in the laser fields. The dense γ-photons then collide with the focused counter-propagating lasers to initiate the multi-photon Breit-Wheeler process. Particle-in-cell simulations indicate that one may generate a high-yield (1.05 × 10
) overdense (4 × 10
cm
) GeV positron beam using 10 PW scale lasers. Such a bright pair source has many practical applications and could be basis for future compact high-luminosity electron-positron colliders.
Although several laser-plasma-based methods have been proposed for generating energetic electrons, positrons and γ-photons, manipulation of their microstructures is still challenging, and their ...angular momentum control has not yet been achieved. Here, we present and numerically demonstrate an all-optical scheme to generate bright GeV γ-photon and positron beams with controllable angular momentum by use of two counter-propagating circularly-polarized lasers in a near-critical-density plasma. The plasma acts as a 'switching medium', where the trapped electrons first obtain angular momentum from the drive laser pulse and then transfer it to the γ-photons via nonlinear Compton scattering. Further through the multiphoton Breit-Wheeler process, dense energetic positron beams are efficiently generated, whose angular momentum can be well controlled by laser-plasma interactions. This opens up a promising and feasible way to produce ultra-bright GeV γ-photons and positron beams with desirable angular momentum for a wide range of scientific research and applications.
Laser manipulation of nuclear decay has extremely promising applications. In this study, cutting-edge Gaussian lasers were combined with the latest data on α decay to thoroughly investigate the ...factors that impact the penetration probability in laser-assisted α decay of nuclei, while considering the deformation of the nucleus. Our calculations reveal that using state-of-the-art laser fields can marginally alter the half-life of α decay by affecting the penetration probability within a narrow range. Moreover, our findings demonstrate two key points: (1) By deriving an analytical formula for the rate of change of the α decay penetration probability in an ultra-intense laser field, we unveil the negative correlation between the α decay energy and the rate of change of the α decay penetration probability. (2) We attribute the wavelength as the determinant of the effect of the average rate of change of the penetration probability, which we explain by reconstructing the laser pulse width and wavelength. This research offers a rapid method to estimate the rate of change of the α-decay penetration probability and serves as a valuable reference for future experimental investigations of laser-nuclear interactions.
Generation of attosecond bunches of energetic electrons offers significant potential from ultrafast physics to novel radiation sources. However, it is still a great challenge to stably produce such ...electron beams with lasers, since the typical subfemtosecond electron bunches from laser-plasma interactions either carry low beam charge, or propagate for only several tens of femtoseconds. Here we propose an all-optical scheme for generating dense attosecond electron bunches via the interaction of an intense Laguerre-Gaussian (LG) laser pulse with a nanofiber. The dense bunch train results from the unique field structure of a circularly polarized LG laser pulse, enabling each bunch to be phase-locked and accelerated forward with low divergence, high beam charge and large beam-angular-momentum. This paves the way for wide applications in various fields, e.g., ultrabrilliant attosecond x/γ-ray emission.
The radiation trapping effect (RTE) of electrons in the interaction of an ultra-intense laser and a near-critical-density plasma-filled gold cone is numerically investigated by using the ...particle-in-cell code EPOCH. It is found that, by using the cone, the threshold laser intensity for electron trapping can be significantly decreased. The trapped electrons located behind the laser front and confined near the laser axis oscillate significantly in the transverse direction and emit high-energy photons in the forward direction. With parameters optimized, a narrow photon angular distribution and a high-energy conversion efficiency from the laser to the photons can be obtained. The proposed scheme may offer possibilities to demonstrate the RTE of electrons in experiments at approachable laser intensities and serve as a novel table-top ray source.
Introduction to the Topical Issue high field QED physics Yu, Tong-Pu; Pegoraro, Francesco; Sarri, Gianluca ...
The European physical journal. D, Atomic, molecular, and optical physics,
2023/4, Letnik:
77, Številka:
4
Journal Article
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