Niedermayer Uwe, Egenolf Thilo, Boine-Frankenheim Oliver
Technische Universität Darmstadt, Schlossgartenstrasse 8, D-64289 Darmstadt, Germany.
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, D-64291 Darmstadt, Germany.
Phys Rev Lett. 2020 Oct 16;125(16):164801. doi: 10.1103/PhysRevLett.125.164801.
The concept of dielectric-laser acceleration (DLA) provides the highest gradients among breakdown-limited (nonplasma) particle accelerators and thus the potential of miniaturization. The implementation of a fully scalable electron accelerator on a microchip by two-dimensional alternating phase focusing (APF), which relies on homogeneous laser fields and external magnetic focusing in the third direction, was recently proposed. In this Letter, we generalize the APF for DLA scheme to 3D, such that stable beam transport and acceleration is attained without any external equipment, while the structures can still be fabricated by entirely two-dimensional lithographic techniques. In the new scheme, we obtain significantly higher accelerating gradients at given incident laser field by additionally exploiting the new horizontal edge. This enables ultralow injection energies of about 2.5 keV (β=0.1) and bulky high voltage equipment as used in previous DLA experiments can be omitted. DLAs have applications in ultrafast time-resolved electron microscopy and diffraction. Our findings are crucial for the miniaturization of the entire setup and pave the way towards integration of DLAs in optical fiber driven endoscopes, e.g., for medical purposes.
介电激光加速（DLA）的概念在击穿限制（非等离子体）粒子加速器中提供了最高的梯度，因而具有小型化的潜力。最近有人提出通过二维交替相位聚焦（APF）在微芯片上实现完全可扩展的电子加速器，该方法依赖均匀激光场和第三方向的外部磁聚焦。在本信函中，我们将用于DLA方案的APF推广到三维，从而在无需任何外部设备的情况下实现稳定的束流传输和加速，同时结构仍可通过完全二维光刻技术制造。在新方案中，通过额外利用新的水平边缘，我们在给定入射激光场下获得了显著更高的加速梯度。这使得超低注入能量约为2.5 keV（β = 0.1）成为可能，并且可以省略先前DLA实验中使用的笨重高压设备。DLA在超快时间分辨电子显微镜和衍射方面有应用。我们的发现对于整个装置的小型化至关重要，并为将DLA集成到光纤驱动的内窥镜中（例如用于医疗目的）铺平了道路。
