论文标题
极端的灯波电子场从纳米植物发射
Extreme Lightwave Electron Field Emission from a Nanotip
论文作者
论文摘要
我们在极端条件下从钨纳米ips中的电子对电子的亚周期terahertz浅野发射报告，对应于keldysh参数$γ_k\ lot10^{ - 4} $。在照明的纳米植物的顶端实现了高达40 gV/m的局部峰值字段，从而在准静态场中导致亚周期的冷场电子发射和加速度。通过同时测量电子束电荷和能量分布，我们在田间条件下对准静态Fowler-Nordheim隧道理论进行了定量测试，这完全抑制了隧道屏障。观察到了非常高的$ \ sim10^6 $电子/脉冲的高束费用，在当地磁场加速后达到3.5〜KEV的最大能量。即使在这种极端的田间制度中，能量分布和发射电流也与福勒 - 诺德海姆理论良好。将此模型扩展到在这些条件下的单次镜头状态可以预测峰值电子分布，光谱纯度为$ 10^{ - 4} $。观察到THZ场引起的重塑和锐化纳米尺，将尖端半径从120〜nm降低至35〜nm，大约$ 10^9 $ thz射击。这些结果表明，在极端场极限中，THZ驱动的纳米尺是超快电子衍射和显微镜的有希望的电子源。
We report on sub-cycle terahertz light-field emission of electrons from tungsten nanotips under extreme conditions corresponding to a Keldysh parameter $γ_K\approx10^{-4}$. Local peak THz fields up to 40~GV/m are achieved at the apex of an illuminated nanotip, causing sub-cycle cold-field electron emission and acceleration in the quasi-static field. By simultaneous measurement of the electron bunch charge and energy distribution, we perform a quantitative test of quasi-static Fowler-Nordheim tunnelling theory under field conditions that completely suppress the tunnel barrier. Very high bunch charges of $\sim10^6$ electrons/pulse are observed, reaching maximum energies of 3.5~keV after acceleration in the local field. The energy distribution and emission current show good agreement with Fowler-Nordheim theory even in this extreme field regime. Extending this model to the single-shot regime under these conditions predicts peak electron distributions with a spectral purity of $10^{-4}$. THz field-induced reshaping and sharpening of the nanotip is observed, reducing the tip radius from 120~nm to 35~nm over roughly $10^9$ THz shots. These results indicate THz-driven nanotips in the extreme field limit are promising electron sources for ultrafast electron diffraction and microscopy.
