Phase and polarization-controlled strong near-field electron dynamics at isolated nanoparticles

孤立纳米粒子的相位和偏振控制强近场电子动力学

• 批准号: 322422731
• 负责人: Dr. Sergey Zherebtsov
• 金额: --
• 依托单位: National Accelerator Laboratory SLAC
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/322422731?language=en
• 关键词: Phase; polarization; controlled; strong; near

Few-cycle laser pulses with well-defined carrier-envelope phase (CEP) have proven to be an essential tool for controlling electronic strong-field processes in nanoscale systems such as nanoparticles, nanotips, and surface assembled nanostructures with attosecond resolution. Our preliminary work on isolated dielectric nanospheres shows the robustness of the CEP controlled strong near-field-induced recollision process in tailored near-fields up to the intensity regime where the nonlinear charge interaction response significantly contributes to the acceleration process. In this proposal we aim to extend the waveform control of the near-field dynamics by utilizing sub-cycle control of the laser field polarization. One of the key advantages of the precise control of the polarization direction of few-cycle single or two color laser fields is that the time evolution of the strong field driven dynamics can be correlated with the angle-resolved photoemission distribution. Major goals of the proposed work include time-resolved studies of strong field induced emission from nanoscopic systems, sub-cycle resolved tracing of the optical response of nanoscopic materials, and the sub-cycle control of the direct and backscattered electrons at the nanoscale. More specifically:1) We will apply near circularly polarized few-cycle laser fields to isolated nanoparticles and image the photoemission projection onto the polarization plane. Information obtained from the angle-resolved distributions will be utilized for momentum-to-time mapping of the photoemission process. With this approach we aim to time-resolve the electron emission from solids in the nonadiabatic tunneling regime.2) We plan to utilize sub-cycle transients of polarization-shaped laser fields to trace the near-field response of nanoscopic systems by imaging the strong field induced photoemission. We will combine the fundamental and second harmonic circular polarized laser pulses with opposite helicity to obtain a cloverleaf shaped laser field. The direction of the cloverleaf shaped field maxima is determined by the relative phase of fundamental and second harmonic pulses and thus depends sensitively on the optical response of the material at these frequencies. We will apply this technique for the investigation of the optical response of isolated nanoparticles in strong-field regime.3) We propose to utilize few-cycle laser pulses of linear and circular polarization in VIS and NIR spectral regions to explore optical control of the electron photoemission from isolated nanoparticles and clusters. With the directional control of the direct and back-scattered electron emission we aim for the creation of synchronized beams of isolated attosecond bursts of electrons. A nanoscopic source of optically controlled electrons can be of interest from the fundamental perspective of laser-matter interaction and in view of applications in ultrafast nanoelectronics and microscopy with ultrashort electron pulses.

具有明确载流子包络相位(CEP)的几个周期的激光脉冲已被证明是控制纳米级系统中电子强场过程的重要工具，例如纳米粒子、纳米针尖和具有阿秒分辨率的表面组装纳米结构。我们在孤立的介电纳米球上的初步工作表明，CEP控制的强近场诱导的再碰撞过程在可剪裁的近场中一直到非线性电荷相互作用响应对加速过程有显著贡献的强度区域都是健壮的。在这个方案中，我们的目的是通过利用激光偏振的子周期控制来扩展近场动力学的波形控制。精确控制少周期单色或双色激光场的偏振方向的关键优点之一是，强场驱动动力学的时间演化可以与角分辨的光电子能分布相关联。拟议工作的主要目标包括纳米系统强场诱导发射的时间分辨研究，纳米材料光学响应的亚循环分辨跟踪，以及在纳米尺度上直接和背向散射电子的亚循环控制。更具体地说：1)我们将对孤立的纳米粒子施加近圆偏振的几个周期的激光场，并将光电子发射投影成像到偏振平面上。从角度分辨分布中获得的信息将被用来绘制光电发射过程的动量-时间图。通过这种方法，我们的目标是在非绝热隧穿过程中时间分辨固体中的电子发射。2)我们计划通过成像强场感生光电子发射来利用偏振型激光场的亚周期瞬变来跟踪纳米系统的近场响应。我们将具有相反螺旋度的基频和二次谐波圆偏振激光脉冲组合在一起，得到三叶草形状的激光场。三叶草形场极大值的方向由基频和二次谐波脉冲的相对相位决定，因此敏感地依赖于材料在这些频率下的光学响应。我们将把这项技术应用于研究孤立纳米粒子在强场下的光学响应。3)我们提出在可见光和近红外光谱区域利用几个周期的线偏振和圆偏振激光脉冲来探索孤立纳米粒子和团簇的电子光致发射的光学控制。通过对直接和反向散射电子发射的定向控制，我们的目标是创造孤立的阿秒电子爆发的同步光束。从激光-物质相互作用的基本观点以及在超快纳米电子学和具有超短电子脉冲的显微镜中的应用来看，光学控制电子源的纳米级可以引起人们的兴趣。