A linearly polarized Laguerre–Gaussian(LP-LG)laser beam with a twist index l=−1 has field structure that fundamentally differs from the field structure of a conventional linearly polarized Gaussian beam.Close to the ...A linearly polarized Laguerre–Gaussian(LP-LG)laser beam with a twist index l=−1 has field structure that fundamentally differs from the field structure of a conventional linearly polarized Gaussian beam.Close to the axis of the LP-LG beam,the longitudinal electric and magnetic fields dominate over the transverse components.This structure offers an attractive opportunity to accelerate electrons in vacuum.It is shown,using three-dimensional particle-in-cell simulations,that this scenario can be realized by reflecting an LP-LG laser off a plasma with a sharp density gradient.The simulations indicate that a 600 TW LP-LG laser beam effectively injects electrons into the beam during the reflection.The electrons that are injected close to the laser axis experience a prolonged longitudinal acceleration by the longitudinal laser electric field.The electrons form distinct monoenergetic bunches with a small divergence angle.The energy in the most energetic bunch is 0.29 GeV.The bunch charge is 6 pC and its duration is approximately 270 as.The divergence angle is just 0.57°(10 mrad).By using a linearly polarized rather than a circularly polarized Laguerre–Gaussian beam,our scheme makes it easier to demonstrate the electron acceleration experimentally at a high-power laser facility.展开更多
基金Y.S. acknowledges the support by USTC Research Funds of the Double First-Class Initiative, Strategic Priority Research Program of CAS (Grant No. XDA25010200)CAS Project for Young Scientists in Basic Research (Grant No. YSBR060)+1 种基金Newton International Fellows Alumni follow-on fundingD.R.B. and A.A. acknowledge the support by the National Science Foundation (Grant No. PHY 1903098)。
文摘A linearly polarized Laguerre–Gaussian(LP-LG)laser beam with a twist index l=−1 has field structure that fundamentally differs from the field structure of a conventional linearly polarized Gaussian beam.Close to the axis of the LP-LG beam,the longitudinal electric and magnetic fields dominate over the transverse components.This structure offers an attractive opportunity to accelerate electrons in vacuum.It is shown,using three-dimensional particle-in-cell simulations,that this scenario can be realized by reflecting an LP-LG laser off a plasma with a sharp density gradient.The simulations indicate that a 600 TW LP-LG laser beam effectively injects electrons into the beam during the reflection.The electrons that are injected close to the laser axis experience a prolonged longitudinal acceleration by the longitudinal laser electric field.The electrons form distinct monoenergetic bunches with a small divergence angle.The energy in the most energetic bunch is 0.29 GeV.The bunch charge is 6 pC and its duration is approximately 270 as.The divergence angle is just 0.57°(10 mrad).By using a linearly polarized rather than a circularly polarized Laguerre–Gaussian beam,our scheme makes it easier to demonstrate the electron acceleration experimentally at a high-power laser facility.
