论文标题
两局级联等离子体中的强度冲浪和带宽延伸的Terahertz辐射
Intensity-surged and Bandwidth-extended Terahertz Radiation in Two-foci Cascading Plasmas
论文作者
论文摘要
气体介质中的两色强场混合是一种广泛使用的方法，可以产生明亮的宽带Terahertz（THZ）辐射。在这里，我们提出了一种新的违反直觉方法，以两种彩色方案促进THZ性能。除了我们知道，最大THZ产生的两种焦点是重叠的，我们发现，当两彩色光束的焦点明显沿传播轴明显分离，导致等离子体的血浆时，THZ转换效率就会飙升至100美元，$ 10^$ 3^$ 3^$ 3^$ 3^$ 3^$ 3^$ 3^$ 3^ - 带宽在800/400 nm的条件下，$ \ sim $ 35 FS驾驶激光器。借助脉冲传播方程和光电流模型，可以通过在级联等离子体中激光能量的空间重新分布引起的THZ产生和吸收之间的折衷来部分理解观测值。当前的方法可以扩展到中红外驾驶激光器，并且预计THZ峰值功率和转换效率的新记录。
The two-color strong-field mixing in gas medium is a widely-used approach to generate bright broadband terahertz (THz) radiation. Here, we present a new and counterintuitive method to promote THz performance in two-color scheme. Beyond our knowledge that the maximum THz generation occurs with two-color foci overlapped, we found that, when the foci of two-color beams are noticeably separated along the propagation axis resulting in cascading plasmas, the THz conversion efficiency is surged by one order of magnitude and the bandwidth is stretched by more than 2 times, achieving $10^{-3}$ conversion efficiency and $>$100 THz bandwidth under the condition of 800/400 nm, $\sim$35 fs driving lasers. With the help of the pulse propagation equation and photocurrent model, the observations can be partially understood by the compromise between THz generation and absorption due to the spatial redistribution of laser energy in cascading plasmas. Present method can be extended to mid-infrared driving laser, and the new records of THz peak power and conversion efficiency are expected.
