Controlling the delivery of multi-terawatt and petawatt laser pulses to final focus, both in position and angle, is critical to many laser applications such as optical guiding, laser–plasma acceleration, and laser-produced secondary radiation. We present an online, non-destructive laser diagnostic, capable of measuring the transverse position and pointing angle at focus. The diagnostic is based on a unique double-surface-coated wedged-mirror design for the final steering optic in the laser line, producing a witness beam highly correlated with the main beam. By propagating low-power kilohertz pulses to focus, we observed spectra of focus position and pointing angle fluctuations dominated by frequencies below 70 Hz. The setup was also used to characterize the excellent position and pointing angle correlation of the 1 Hz high-power laser pulses to this low-power kilohertz pulse train, opening a promising path to fast non-perturbative feedback concepts even on few-hertz-class high-power laser systems.

中文翻译：

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在 100-TW 级激光脉冲的最终焦点处进行高功率非微扰激光传输诊断

在位置和角度上控制多太瓦和拍瓦激光脉冲到最终焦点的传输对于许多激光应用（例如光导、激光等离子体加速和激光产生的二次辐射）至关重要。我们提出了一种在线无损激光诊断，能够测量焦点处的横向位置和指向角。该诊断基于独特的双面涂层楔形镜设计，用于激光线中的最终转向光学元件，产生与主光束高度相关的见证光束。通过传播低功率千赫兹脉冲进行聚焦，我们观察到焦点位置的光谱和由低于 70 Hz 的频率支配的指向角波动。