论文标题
带有轨道角动量的自种自节日激光器
Self-Seeded Free-Electron Lasers with Orbital Angular Momentum
论文作者
论文摘要
带有轨道角动量（OAM）的X射线梁是用于探测物质的新兴工具。光学元件（例如螺旋相和区域板）已被广泛用于生成绿色光。但是，由于强度较高，这些光学元件在X射线自由电子激光器（XFELS）上使用挑战。在这里，我们提出了一种自种的FEL方法来产生强烈的X射线涡旋。与放大后的被动过滤不同，光学元件将用于在线性方向上引入螺旋相，从而大大降低了光学元件上的热载荷。然后将产生的OAM脉冲用作种子并显着放大。理论分析和数值模拟表明，可以通过两个以上的数量级来扩增OAM种子脉冲的功率，从而达到了几十吉瓦的峰值。所提出的方法为Xfel Light的高功率和高重复速率OAM脉冲铺平了道路。
X-ray beams carrying orbital angular momentum (OAM) are an emerging tool for probing matter. Optical elements, such as spiral phase plates and zone plates, have been widely used to generate OAM light. However, these optics are challenging to use at x-ray free-electron lasers (XFELs) due to the high impinging intensities. Here, we propose a self-seeded FEL method to produce intense x-ray vortices. Unlike passive filtering after amplification, an optical element will be used to introduce the helical phase in the linear regime, significantly reducing the thermal load on the optical element. The generated OAM pulse is then used as a seed and significantly amplified. Theoretical analysis and numerical simulations demonstrate that the power of the OAM seed pulse can be amplified by more than two orders of magnitude, reaching peak powers of several tens of gigawatts. The proposed method paves the way for high-power and high-repetition-rate OAM pulses of XFEL light.
