Isolated attosecond pulses are useful to perform pump–probe experiments at a high temporal resolution, and provide a new tool for ultrafast metrology. However, it is still a challenging task to generate such pulses of high intensity, even for a few-cycle laser. Through particle-in-cell simulations, we show that it is possible to directly generate a giant isolated attosecond pulse in the transmission direction from relativistic laser-driven plasmas. Compared to attosecond pulse generation in the reflection direction, no further spectral filtering is needed. The underlying radiation mechanism is coherent synchrotron emission, and the transmitted isolated attosecond pulse can reach relativistic intensity. This provides a promising alternative to generate intense isolated attosecond pulses for ultrafast studies.

中文翻译：

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从激光驱动等离子体的传输中直接产生相对论性孤立的阿秒脉冲

孤立的阿秒脉冲对于以高时间分辨率执行泵浦探针实验非常有用，并为超快速计量提供了新工具。但是，即使对于几个周期的激光器，产生这种高强度的脉冲仍然是一项艰巨的任务。通过单元中的粒子模拟，我们表明可以从相对论激光驱动的等离子体沿传输方向直接生成一个巨大的孤立的阿秒脉冲。与在反射方向上产生阿秒脉冲相比，不需要进一步的光谱滤波。潜在的辐射机制是相干同步加速器发射，并且透射的孤立阿秒脉冲可以达到相对论强度。这提供了一种有希望的替代方案，可以产生强烈的孤立的阿秒脉冲，用于超快研究。