A concept of the front-end system of the XCELS (eXawatt Center for Extreme Light Studies) facility is presented. Its design is aimed at achieving high stability of laser radiation parameters and possibility of their control in a wide range. Optically synchronised chirped signal (wavelength 910 nm, bandwidth more than 100 nm, and duration ∼3 ns) and pump (wavelength 1054 nm, bandwidth ∼1 nm, and duration ∼4 ns) pulses for XCELS parametric amplifiers will be implemented at the output of the front-end system. Chirped femtosecond pulses with energies above 100 mJ [no more than 15 fs long after compression, with carrier-envelope phase (CEP) stabilisation] will have a repetition rate up to 100 Hz, which will allow one to implement active energy stabilisation and to minimise the angular jitter of the emitted beam at the XCELS output. The application of picosecond pumping in the parametric amplifier of the front-end system should provide a high contrast of femtosecond pulses. The pump pulse will be linearly frequency-modulated; this approach will not affect the parametric amplification efficiency but make it possible to use spectral methods to control the pump pulse shape in order to form a pulse of specified shape at the output of power amplifiers, even under conditions of their strong saturation.

介绍了 XCELS（eXawatt 极光研究中心）设施的前端系统的概念。其设计旨在实现激光辐射参数的高稳定性和大范围控制的可能性。XCELS 参量放大器的光学同步啁啾信号（波长 910 nm，带宽超过 100 nm，持续时间 ~3 ns）和泵浦（波长 1054 nm，带宽 ~1 nm，持续时间 ~4 ns）脉冲将在输出端实现前端系统的介绍。能量超过 100 mJ 的啁啾飞秒脉冲 [压缩后不超过 15 fs，具有载波包络相位 (CEP) 稳定] 将具有高达 100 Hz 的重复率，这将允许实现有源能量稳定并最小化XCELS 输出处发射光束的角度抖动。皮秒泵浦在前端系统参量放大器中的应用应提供高对比度的飞秒脉冲。泵浦脉冲将被线性调频；这种方法不会影响参数放大效率，但可以使用频谱方法来控制泵浦脉冲形状，以便在功率放大器的输出端形成特定形状的脉冲，即使在它们的强饱和条件下也是如此。