Direct fluorescence characterisation of a picosecond seeded optical parametric amplifier
Direct fluorescence characterisation of a picosecond seeded optical parametric amplifier
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DOI：
10.1016/j.optcom.2014.09.032
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发表时间：
2015-02
影响因子：
2.4
通讯作者：
N. Stuart;D. Bigourd;R. Hill;T. Robinson;K. Mecseki;S. Patankar;G. New;Roland A. Smith
中科院分区：
文献类型：
--
作者：
N. Stuart;D. Bigourd;R. Hill;T. Robinson;K. Mecseki;S. Patankar;G. New;Roland A. Smith
基于光学参量放大（OPA）的高功率激光器的时间强度对比度会受到来自非线性增益级的参量荧光的限制。在这里，我们提出了一种光谱方法，用于直接测量不需要的参数荧光广泛适用于从未接种到完全接种和饱和的OPA操作。我们的技术采用同时光谱的荧光光子稍微超出种子带宽和强烈衰减的光在种子中心波长。为了证明它的适用性，我们已经表征了两级皮秒OPA前置放大器的性能，增益为2.8× 105，提供335 μ J的脉冲在1054 nm。我们发现，从一个强种子OPA的荧光减少了约500倍，从未耗尽到完全泵耗尽制度。我们还确定了真空涨落驱动的噪声项播种这个OPA荧光是0.7±0.4光子ps− 1 nm− 1带宽。所得到的拍摄到拍摄的统计数据突出了荧光高于平均值的5倍增加的1.5%概率和10倍增加的0.3%概率。最后，我们表明，OPA荧光可以被限制在一个几ps的基座与3× 10− 9的时间强度对比度1.3 ps的强激光脉冲，一个水平非常有吸引力的大规模啁啾脉冲OPA激光系统。
The temporal intensity contrast of high-power lasers based on optical parametric amplification (OPA) can be limited by parametric fluorescence from the non-linear gain stages. Here we present a spectroscopic method for direct measurement of unwanted parametric fluorescence widely applicable from unseeded to fully seeded and saturated OPA operation. Our technique employs simultaneous spectroscopy of fluorescence photons slightly outside the seed bandwidth and strongly attenuated light at the seed central wavelength. To demonstrate its applicability we have characterised the performance of a two-stage picosecond OPA pre-amplifier with 2.8× 10 5 gain, delivering 335 μ J pulses at 1054 nm. We show that fluorescence from a strongly seeded OPA is reduced by~ 500× from the undepleted to full pump depletion regimes. We also determine the vacuum fluctuation driven noise term seeding this OPA fluorescence to be 0.7±0.4 photons ps− 1 nm− 1 bandwidth. The resulting shot-to-shot statistics highlights a 1.5% probability of a five-fold and 0.3% probability of a ten-fold increase of fluorescence above the average value. Finally, we show that OPA fluorescence can be limited to a few-ps pedestal with 3× 10− 9 temporal intensity contrast 1.3 ps ahead of an intense laser pulse, a level highly attractive for large scale chirped-pulse OPA laser systems.