论文标题
在负组速度分散下参数下转换的耦合时空相干性的测量
Measurement of coupled spatiotemporal coherence of parametric down-conversion under negative group velocity dispersion
论文作者
论文摘要
我们介绍了在负组速度分散范围内参数下转换的时空相干性的直接测量。在这种情况下，频谱是环形的，并且时间连贯性与空间连贯性耦合。相应地，由于时间延迟的引入，由于空间位移而缺乏相干性。我们基于修改的Mach-Zhhnder干涉仪显示了一种简单的技术，该技术使我们能够同时测量时间连贯性和近场空间相干性，并完全控制两个变量。该技术还适用于测量二阶相干性，其中主要应用与两光子光谱有关。
We present a direct measurement of the spatiotemporal coherence of parametric down-conversion in the range of negative group-velocity dispersion. In this case, the frequency-angular spectra are ring-shaped and temporal coherence is coupled to spatial coherence. Correspondingly, the lack of coherence due to spatial displacement can be compensated with the introduction of time delay. We show a simple technique, based on a modified Mach-Zehnder interferometer, which allowed us to measure time coherence and near-field space coherence simultaneously, with complete control of both variables. This technique will be also suitable for the measurement of second-order coherence, where the main applications are related to the two-photon spectroscopy.
