Valialshchikov M A, Kharin V Yu, Rykovanov S G
High Performance Computing and Big Data Laboratory, Skolkovo Institute of Science and Technology, Moscow 143026, Russia.
Genity LLC, 444 W. Lake Street, Chicago, Illinois 60606, USA.
Phys Rev Lett. 2021 May 14;126(19):194801. doi: 10.1103/PhysRevLett.126.194801.
Nonlinear Compton scattering is a promising source of bright gamma rays. Using readily available intense laser pulses to scatter off the energetic electrons, on the one hand, allows us to significantly increase the total photon yield, but on the other hand, leads to a dramatic spectral broadening of the fundamental emission line as well as its harmonics due to the laser pulse shape induced ponderomotive effects. In this Letter we propose to avoid ponderomotive broadening in harmonics by using the polarization gating technique-a well-known method to construct a laser pulse with temporally varying polarization. We show that by restricting harmonic emission only to the region near the peak of the pulse, where the polarization is linear, it is possible to generate a bright narrow bandwidth comb in the gamma region.
非线性康普顿散射是一种很有前景的明亮伽马射线源。一方面，利用易于获得的强激光脉冲与高能电子相互散射，能使我们显著提高总光子产额，但另一方面，由于激光脉冲形状引起的有质动力效应，会导致基频发射线及其谐波出现显著的光谱展宽。在本信函中，我们提议通过使用偏振选通技术——一种构建具有随时间变化偏振的激光脉冲的知名方法，来避免谐波中的有质动力展宽。我们表明，通过将谐波发射仅限制在脉冲峰值附近的区域（此处偏振是线性的），有可能在伽马区域产生明亮的窄带宽梳状谱。
