School of Mechanical and Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea.
Center for Quantum-Beam-based Radiation Research, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057, South Korea.
Sci Rep. 2017 Jan 9;7:39966. doi: 10.1038/srep39966.
Ultrafast electron-based coherent radiation sources, such as free-electron lasers (FELs), ultrafast electron diffraction (UED) and Thomson-scattering sources, are becoming more important sources in today's ultrafast science. Photocathode laser is an indispensable common subsystem in these sources that generates ultrafast electron pulses. To fully exploit the potentials of these sources, especially for pump-probe experiments, it is important to achieve high-precision synchronization between the photocathode laser and radio-frequency (RF) sources that manipulate electron pulses. So far, most of precision laser-RF synchronization has been achieved by using specially designed low-noise Er-fibre lasers at telecommunication wavelength. Here we show a modular method that achieves long-term (>1 day) stable 10-fs-level synchronization between a commercial 79.33-MHz Ti:sapphire laser oscillator and an S-band (2.856-GHz) RF oscillator. This is an important first step toward a photocathode laser-based femtosecond RF timing and synchronization system that is suitable for various small- to mid-scale ultrafast X-ray and electron sources.
基于超快电子的相干辐射源，如自由电子激光（FEL）、超快电子衍射（UED）和汤姆逊散射源，在当今的超快科学中变得越来越重要。光电子源是这些光源中不可缺少的常见子系统，它可以产生超快电子脉冲。为了充分发挥这些光源的潜力，特别是在泵浦探测实验中，实现光电子源和操纵电子脉冲的射频（RF）源之间的高精度同步非常重要。到目前为止，大多数精密激光-RF 同步都是通过使用专门设计的电信波长的低噪声 Er 光纤激光器来实现的。在这里，我们展示了一种模块化方法，可以在商业的 79.33-MHz Ti：蓝宝石激光振荡器和 S 波段（2.856-GHz）RF 振荡器之间实现长期（>1 天）稳定的 10-fs 级同步。这是朝着基于光电子源的飞秒 RF 定时和同步系统迈出的重要的第一步，该系统适用于各种小型到中型的超快 X 射线和电子源。
