摘要
We propose a new laser-plasma-based method to generate brightγ-rays carrying large orbital angular momentum by interacting a circularly polarized Laguerre–Gaussian laser pulse with a near-critical hydrogen plasma conflned in an over-dense solid tube.In the flrst stage of the interaction,it is found via fully relativistic three-dimensional particle-in-cell simulations that high-energy helical electron beams with large orbital angular momentum are generated.In the second stage,this electron beam interacts with the laser pulse reflected from the plasma disc behind the solid tube,and helicalγbeams are generated with the same topological structure as the electron beams.The results show that the electrons receive angular momentum from the drive laser,which can be further transferred to theγphotons during the interaction.Theγbeam orbital angular momentum is strongly dependent on the laser topological charge l and laser intensity a_(0),which scales as L_(γ)∝a_(0)~4.A short(duration of 5 fs)isolated helicalγbeam with an angular momentum of-3.3×10^(-14)kg m~2 s^(-1)is generated using the Laguerre–Gaussian laser pulse with l=2.The peak brightness of the helicalγbeam reaches 1.22×10^(24)photons s^(-1)mm^(-2)mrad^(-2)per 0.1%BW(at 10 Me V),and the laser-to-γ-ray angular momentum conversion rate is approximately 2.1%.
作者
Mamat Ali BAKE
唐琐
谢柏松
Mamat Ali BAKE;Suo TANG;Baisong XIE(Xinjiang Key Laboratory of Solid State Physics and Devices,Xinjiang University,Urumqi 830046,Peopleʼs Republic of China;School of Physics Science and Technology,Xinjiang University,Urumqi 830046,Peopleʼs Republic of China;Key Laboratory of Beam Technology of the Ministry of Education,and College of Nuclear Science and Technology,Beijing Normal University,Beijing 100875,Peopleʼs Republic of China;College of Physics and Optoelectronic Engineering,Ocean University of China,Qingdao 266100,Peopleʼs Republic of China)
基金
flnancially supported by National Natural Science Foundation of China(Nos.11664039,11964038,12104428,and 11875007)
support from the Young Talents Project at Ocean University of China。