Fu Yuxi, Takahashi Eiji J, Midorikawa Katsumi
Opt Express. 2016 Jun 13;24(12):13276-87. doi: 10.1364/OE.24.013276.
We demonstrate a method of stabilizing the carrier-envelope phase (CEP) of low-repetition-rate, high-energy femtosecond laser systems such as TW-PW class lasers. A relatively weak high-repetition-rate (~1 kHz) reference pulse copropagates with a low-repetition-rate (10 Hz) high-energy pulse, which are s- and p-polarized, respectively. Using a Brewster angle window, the reference pulse is separated after the power amplifier and used for feedback to stabilize its CEP. The single-shot CEP of the high-energy pulse is indirectly stabilized to 550 mrad RMS, which is the highest CEP stability ever reported for a low-repetition-rate (10-Hz) high-energy laser system. In this novel method, the feedback frequency of the reference pulse from the front-end preamplifier can be almost preserved. Thus, higher CEP stability can be realized than for lower frequencies. Of course, a reference pulse with an even higher repetition rate (e.g., 10 kHz) can be easily employed to sample and feed back CEP jitter over a broader frequency bandwidth.
我们展示了一种稳定低重复频率、高能量飞秒激光系统（如太瓦 - 拍瓦级激光器）载波包络相位（CEP）的方法。一个相对较弱的高重复频率（约1千赫兹）参考脉冲与一个低重复频率（10赫兹）高能量脉冲共传播，它们分别为s偏振和p偏振。使用一个布儒斯特角窗口，参考脉冲在功率放大器之后被分离出来，并用于反馈以稳定其CEP。高能量脉冲的单次CEP被间接稳定到550毫弧度均方根误差，这是低重复频率（10赫兹）高能量激光系统所报道的最高CEP稳定性。在这种新方法中，来自前端前置放大器的参考脉冲的反馈频率几乎可以保留。因此，与较低频率相比，可以实现更高的CEP稳定性。当然，一个具有更高重复频率（例如10千赫兹）的参考脉冲可以很容易地用于在更宽的频率带宽上采样和反馈CEP抖动。
