Opt Lett. 2023 May 15;48(10):2704-2707. doi: 10.1364/OL.491679.
The dielectric laser accelerator (DLA) is a promising candidate for next-generation table-top and even on-chip particle accelerators. Long-range focusing of a tiny-size electron bunch on chip is crucial for the practical applications of DLA, which has been a challenge. Here we propose a bunch focusing scheme, which uses a pair of readily available few-cycle terahertz (THz) pulses to drive an array of millimeter-scale prisms via the inverse Cherenkov effect. The THz pulses are reflected and refracted multiple times through the prism arrays, synchronizing with and periodically focusing the electron bunch along the bunch channel. Cascade bunch-focusing is realized by making the electromagnetic field phase experienced by electrons in each stage of the array, that is, the synchronous phase, in the focusing phase region. The focusing strength can be adjusted via changing the synchronous phase and THz field intensity, optimization of which will sustain the stable bunch transportation in a tiny-size bunch channel on chip. This bunch-focusing scheme sets a base for developing a long-acceleration-range and high-gain DLA.
介电激光加速器（DLA）是下一代台式甚至片上粒子加速器的有前途的候选者。在芯片上对微小尺寸电子束进行长程聚焦对于 DLA 的实际应用至关重要，这一直是一个挑战。在这里，我们提出了一种束聚焦方案，该方案使用一对现成的几周期太赫兹（THz）脉冲通过逆切伦科夫效应驱动毫米级棱镜阵列。THz 脉冲通过棱镜阵列多次反射和折射，与电子束同步并沿束通道周期性地聚焦电子束。通过使电子在阵列的每个阶段经历的电磁场相位（即同步相位）处于聚焦相位区域来实现级联束聚焦。通过改变同步相位和 THz 场强度来调整聚焦强度，对其进行优化将维持在芯片上微小尺寸束通道中的稳定束传输。这种束聚焦方案为开发长加速距离和高增益的 DLA 奠定了基础。
