Strong Field Acceleration and Steering of Ultrafast Electron Pulses from a Sharp Metallic Nanotip
Strong Field Acceleration and Steering of Ultrafast Electron Pulses from a Sharp Metallic Nanotip
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DOI：
10.1103/physrevlett.109.244803
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发表时间：
2012-12-11
影响因子：
8.6
通讯作者：
Lienau, Christoph
中科院分区：
文献类型：
--
作者：
Park, Doo Jae;Piglosiewicz, Bjoern;Lienau, Christoph
我们报道了一种强激光场诱导的改变纳米金锥体发射的超短电子脉冲传播方向的方法。用波长和强度可变的超快近红外光脉冲激发，记录了从这种针尖发射的电子的角分辨动能谱。对于足够长的波长，我们观察到在锥形尖端的场梯度内电子有显著的强场加速。我们发现最快电子的发射锥角明显变窄。我们将其归因于电场诱导的亚周期电子的转向，而不是颤动电子的发散发射。我们的发现得到了基于修正的Simpleman模型的模拟的证实，该模型在尖端附近加入了弯曲的矢量场梯度。我们的结果为设计高定向纳米尺寸超快电子源提供了新的途径。DOI：10.1103/PhysRevLett.109.244803
We report a strong, laser-field induced modification of the propagation direction of ultrashort electron pulses emitted from nanometer-sized gold tapers. Angle-resolved kinetic energy spectra of electrons emitted from such tips are recorded using ultrafast near-infrared light pulses of variable wavelength and intensity for excitation. For sufficiently long wavelengths, we observe a pronounced strong-field acceleration of electrons within the field gradient at the taper apex. We find a distinct narrowing of the emission cone angle of the fastest electrons. We ascribe this to the field-induced steering of subcycle electrons as opposed to the diverging emission of quiver electrons. Our findings are corroborated by simulations based on a modified Simpleman model incorporating the curved, vectorial field gradient in the vicinity of the tip. Our results indicate new pathways for designing highly directional nanometer-sized ultrafast electron sources. DOI: 10.1103/PhysRevLett.109.244803