基于等离子体的相对论激光偏振调控元件模拟  

Simulation on Plasma-Based Polarization Optics for Relativistic Laser Pulses

作　　者：庄建州 赵马克 刘哲 彭文杰 孙浩帆 陈翔 冷雨欣 宾建辉[1,2] Zhuang Jianzhou;Zhao Make;Liu Zhe;Peng Wenjie;Sun Haofan;Chen Xiang;Leng Yuxin;Bin Jianhui(School of Microelectronics,Shanghai University,Shanghai 200444,China;State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201200,China)

机构地区：[1]上海大学微电子学院,上海200444 [2]中国科学院上海光学精密机械研究所强场激光物理国家重点实验室,上海201800 [3]上海科技大学物质科学与技术学院,上海201200

出　　处：《光学学报》2025年第2期212-219,共8页Acta Optica Sinica

基　　金：中国科学院稳定支持基础研究领域青年团队计划(YSBR060);国家自然科学基金(61925507)。

摘　　要：由于现有光学器件损伤阈值的限制,往往难以利用现有的光学材料对相对论激光进行偏振调控。当激光与等离子体相互作用,且在激光斜入射靶时,等离子体密度分布不均匀,可以将等离子体类比为双折射晶体,从而实现对相对论激光光场或者相位的调控。通过particle-in-cell(PIC)仿真的方式,对相对论激光与固体密度等离子体相互作用后,透射激光的偏振调控状态进行详细的模拟研究。二维仿真结果表明,在满足特定条件下,等离子体可以作为偏振元件,实现对相对论激光的偏振调控。三维仿真进一步给出了偏振调控的物理机制,即当激光斜入射靶时,等离子体在不同方向上的不均匀加热带来密度各向异性。上述结果有助于等离子体光学领域的研究,并为未来实验提供了参考。Objective Recently,plasma optics have gained significant attention due to their high damage threshold,making them ideal for ultrafast,ultraintense lasers.Novel concepts for plasma-based photonic devices have been proposed,including plasma mirrors,plasma lenses,plasma gratings,plasma wave plates,and plasma polarizers.For example,plasma-based polarizers have been demonstrated at Lawrence Livermore National Laboratory using low-density gas targets.However,polarization optics based on solid,dense plasmas have not been widely explored.In this paper,we propose a new design for plasma polarization optics based on overdense,nanometer-thin foils.We investigate this concept using particle-in-cell(PIC)simulations.By carefully adjusting plasma parameters,the nanometer-thin foil behaves like a linear polarizer or a quarter-wave plate.This behavior is driven by the inhomogeneity of the plasma density distribution resulting from the interaction,as confirmed by three-dimensional PIC simulations.Methods We investigate plasma polarization optics using the epoch code,conducting both two-dimensional(2D)and three-dimensional(3D)simulations.A nanometer-thin foil composed of protons and electrons is placed in the simulated region,with dimensions of 50λ×20λfor the 2D simulation and 20λ×10λ×10λfor the 3D simulation.These regions are divided into 50000×500 and 4000×500×500 grids,respectively.A circularly polarized laser with 800 nm wavelength and a 2.5μm spot size is focused onto the target and propagates along the x-axis,with peak intensities of 1×1020,5×1020,9×1020 W/cm^(2).The electron density of the targets is set to 50n c,100n c,and 150n c,with target thickness varying from 0.01λto 0.40λ.The polarization of the transmitted laser is calculated by integrating the laser energy along the Ey and Ez components,and the phase is estimated from the mean phase difference between the local maxima of the electric field.The 2D electron density distribution from the 3D simulations is extracted by lineout along the center of the y-

关 键 词：激光等离子体相互作用 超强超短激光 偏振调控 PIC仿真 

分 类 号：O436[机械工程—光学工程]