ABSTRACT

This study investigates recent advances in photoelectron emission generated by irradiating ultrashort lasers on metallic nanostructures and low-dimensional carbon materials. Recently, primary focus has been on improving the efficiency of emitters, i.e. increasing the number of field-emitted electrons and their respective kinetic energies. An example of this is the modification of the conventional metal nanotip through adiabatic nanofocusing and various plasmonic metal structures, such as nanorods and bowtie antenna. The coherent emission control with two color irradiation enabled modulation in the emission yield. In addition, THz waves near the metallic nanostructure induced a highly accelerated, monochromatic energy. Alternative to metallic nanotips, carbon nanotubes are emerging as efficient photoelectron emitters, due to the large enhancement factor associated with their high aspect ratio and damage threshold. They particularly allowed the use of femtosecond light sources with a relatively short wavelength, resulting in the generation of photoelectrons with a narrow bandwidth. Additionally, electronic control over the single-walled nanotubes band structure added a degree of freedom for controlling the electron emission yield. Finally, we review the strong-field tunneling emission in graphene edge, with the emission yield showing an anomalous increase of nonlinear order, corresponding to the deep strong tunneling regime.

摘要

这项研究调查了在金属纳米结构和低维碳材料上照射超短激光所产生的光电子发射的最新进展。近来，主要关注点是提高发射器的效率，即增加场发射电子的数量及其各自的动能。这方面的一个例子是通过绝热纳米聚焦和各种等离激元金属结构，例如纳米棒和领结天线，对常规金属纳米尖端进行了修饰。具有两种颜色照射的相干发射控制使得能够调节发射产量。另外，金属纳米结构附近的太赫兹波诱发了高度加速的单色能量。碳纳米管可以替代金属纳米尖端，是高效的光电子发射器，由于与高纵横比和损伤阈值相关的增强因素较大。他们特别允许使用波长相对较短的飞秒光源，从而产生了带宽较窄的光电子。另外，对单壁纳米管能带结构的电子控制增加了控制电子发射产率的自由度。最后，我们回顾了石墨烯边缘的强场隧穿发射，其发射率显示出非线性阶数的反常增加，与深层强隧穿机制相对应。另外，对单壁纳米管能带结构的电子控制增加了控制电子发射产率的自由度。最后，我们回顾了石墨烯边缘的强场隧穿发射，其发射率显示出非线性阶数的反常增加，与深层强隧穿机制相对应。另外，对单壁纳米管能带结构的电子控制增加了控制电子发射产率的自由度。最后，我们回顾了石墨烯边缘的强场隧穿发射，其发射率显示出非线性阶数的反常增加，与深层强隧穿机制相对应。