Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
School of Science, Xi'an Jiaotong University, Xi'an 710049, China.
Phys Rev Lett. 2018 Aug 17;121(7):074801. doi: 10.1103/PhysRevLett.121.074801.
Gamma-ray beams with a large angular momentum may affect astrophysical phenomena, which calls for appropriate earth-based experimental investigations. For this purpose, we investigate the generation of well-collimated γ-ray beams with a very large orbital angular momentum using nonlinear Compton scattering of a strong laser pulse of twisted photons at ultrarelativistic electrons. Angular momentum conservation among absorbed laser photons, quantum radiation, and electrons is numerically demonstrated in the quantum radiation-dominated regime. We point out that the angular momentum of the absorbed laser photons is not solely transferred to the emitted γ photons, but due to radiation reaction shared between the γ photons and interacting electrons. The efficiency of the angular momentum transfer is optimized with respect to the laser and electron beam parameters. The accompanying process of electron-positron pair production is furthermore shown to enhance the orbital angular momentum gained by the γ-ray beam.
具有大角动量的伽马射线束可能会影响天体物理现象，这就需要进行适当的基于地球的实验研究。为此，我们利用超强激光扭曲光子与相对论电子的非线性康普顿散射，研究了具有非常大轨道角动量的准直伽马射线束的产生。在量子辐射主导的区域，数值证明了吸收的激光光子、量子辐射和电子之间角动量守恒。我们指出，吸收的激光光子的角动量不仅传递给了发射的γ光子，而且由于γ光子和相互作用的电子之间的辐射反应而被共享。角动量转移的效率可以通过激光和电子束参数进行优化。此外，还表明电子-正电子对产生的伴随过程增强了γ射线束获得的轨道角动量。
