Broaddus Payton, Egenolf Thilo, Black Dylan S, Murillo Melanie, Woodahl Clarisse, Miao Yu, Niedermayer Uwe, Byer Robert L, Leedle Kenneth J, Solgaard Olav
Department of Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, California 94305-9505, USA.
Technische Universität Darmstadt, Institut für Teilchenbeschleunigung und Elektromagnetische Felder (TEMF), Schloßgartenstraße 8, 64289 Darmstadt, Germany.
Phys Rev Lett. 2024 Feb 23;132(8):085001. doi: 10.1103/PhysRevLett.132.085001.
We demonstrate a silicon-based electron accelerator that uses laser optical near fields to both accelerate and confine electrons over extended distances. Two dielectric laser accelerator (DLA) designs were tested, each consisting of two arrays of silicon pillars pumped symmetrically by pulse front tilted laser beams, designed for average acceleration gradients 35 and 50 MeV/m, respectively. The DLAs are designed to act as alternating phase focusing (APF) lattices, where electrons, depending on the electron-laser interaction phase, will alternate between opposing longitudinal and transverse focusing and defocusing forces. By incorporating fractional period drift sections that alter the synchronous phase between ±60° off crest, electrons captured in the designed acceleration bucket experience half the peak gradient as average gradient while also experiencing strong confinement forces that enable long interaction lengths. We demonstrate APF accelerators with interaction lengths up to 708 μm and energy gains up to 23.7±1.07 keV FWHM, a 25% increase from starting energy, demonstrating the ability to achieve substantial energy gains with subrelativistic DLA.
我们展示了一种基于硅的电子加速器，它利用激光光学近场在较长距离上对电子进行加速和约束。测试了两种介质激光加速器（DLA）设计，每种设计都由两排硅柱阵列组成，由脉冲前沿倾斜的激光束对称泵浦，分别设计用于平均加速梯度为35和50 MeV/m。DLA被设计为交替相位聚焦（APF）晶格，其中电子根据电子与激光的相互作用相位，在相反的纵向和横向聚焦与散焦力之间交替。通过纳入分数周期漂移段，使同步相位在离波峰±60°之间变化，被捕获在设计加速桶中的电子所经历的峰值梯度是平均梯度的一半，同时还经历强大的约束力，从而实现较长的相互作用长度。我们展示了相互作用长度高达708μm、能量增益高达23.7±1.07 keV FWHM的APF加速器，相对于起始能量增加了25%，证明了使用亚相对论DLA实现可观能量增益的能力。
