The generation of ultra-relativistic positron beams with short duration($\tau_{e^+} \leq 30$ fs), small divergence ($\theta_{e^+} \simeq 3$ mrad), andhigh density ($n_{e^+} \simeq 10^{14} - 10^{15}$ cm$^{-3}$) from a fullyoptical setup is reported. The detected positron beam propagates with ahigh-density electron beam and $\gamma$-rays of similar spectral shape and peakenergy, thus closely resembling the structure of an astrophysical leptonic jet.It is envisaged that this experimental evidence, besides the intrinsicrelevance to laser-driven particle acceleration, may open the pathway for thesmall-scale study of astrophysical leptonic jets in the laboratory.
展开▼
