Spatio-spectral couplings in saturated collinear OPCPA.
Spatio-spectral couplings in saturated collinear OPCPA.
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DOI：
10.1364/oe.448551
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发表时间：
2022-01
期刊：
影响因子：
3.8
通讯作者：
T. Eichner;T. Hülsenbusch;J. Dirkwinkel;T. Lang;L. Winkelmann;G. Palmer;A. Maier
中科院分区：
文献类型：
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作者：
T. Eichner;T. Hülsenbusch;J. Dirkwinkel;T. Lang;L. Winkelmann;G. Palmer;A. Maier
具有高时空光束质量和优异能量稳定性的超快激光脉冲在许多应用中至关重要。在这里，我们提出了一种具有高光束质量和能量稳定性的种子激光器，基于共线光学参量啁啾脉冲放大（OPCPA）级，在1 kHz重复率下提供具有25 fs傅立叶极限的46 μJ脉冲。虽然OPCPA级的饱和对于实现最高可能的能量稳定性是必要的，但它也导致光束质量的劣化。使用模拟，我们表明，光谱相关的，旋转对称的像差占主导地位的共线OPCPA饱和。我们通过实验来表征这些像差，然后去除不同的空间频率，以大大提高光束质量的光谱均匀性，同时保持70小时内测量的0.2%rms的出色能量稳定性。
Ultrafast laser pulses featuring both high spatio-temporal beam quality and excellent energy stability are crucial for many applications. Here, we present a seed laser with high beam quality and energy stability, based on a collinear optical parametric chirped pulse amplification (OPCPA) stage, delivering 46 µJ pulses with a 25 fs Fourier limit at 1 kHz repetition rate. While saturation of the OPCPA stage is necessary for achieving the highest possible energy stability, it also leads to a degradation of the beam quality. Using simulations, we show that spectrally dependent, rotationally symmetric aberrations dominate the collinear OPCPA in saturation. We experimentally characterize these aberrations and then remove distinct spatial frequencies to greatly improve the spectral homogeneity of the beam quality, while keeping an excellent energy stability of 0.2 % rms measured over 70 hours.