论文标题
在自由电子激光振荡器中使用轨道角动量产生X射线
Generating X-rays with orbital angular momentum in free-electron laser oscillator
论文作者
论文摘要
在短波长下，从自由电子激光器上携带轨道角动量（OAM）的光束产生引起了很多关注，作为几个领域和应用中的关键资源。本文中，我们提出了一种轻松的方法，可以从X射线自由电子激光振荡器（XFelo）中产生强烈而相干的OAM梁。我们在纵向和横向模式中都使用Bragg晶体作为反射器和模式选择器，这使指定的共振偏差最大化了高阶OAM感兴趣模式的单通路增益。这可以允许在典型的Xfelo配置中放大和饱和。我们的结果表明，可以在不使用任何外部元素（例如光学模式转换器或椭圆极化的未驱动器）的情况下生成150〜 $ $ J完全相干，硬X射线脉冲，而无需使用任何外部元素。这种简单明了的方法可以为X射线自由电子激光振荡器的横向模式操作的进一步定制铺平道路。
The generation of light beams carrying orbital angular momentum (OAM) from a free-electron laser at short wavelengths has attracted considerable attention as a key resource in several fields and applications. Herein, we present a facile method to generate intense and coherent OAM beams from an X-ray free-electron laser oscillator (XFELO). We use the Bragg crystal as both a reflector as well as mode selector, in both longitudinal and transverse modes, which enables the specified resonance deviation that maximizes the single-pass gain of the high-order OAM mode of interest. This can allow the amplification and saturation of OAM beams in a typical XFELO configuration. Our results show that 150~$μ$J fully coherent, hard-X-ray pulses carrying first-order OAM can be generated without utilizing any external elements such as optical mode converters or elliptically polarized undulators. This simple and straightforward method can pave the way for the further customization of the transverse-mode operation of X-ray free-electron laser oscillators.
