One method to produce pure heralded single photons (HSP) when using the optical process of spontaneous parametric down-conversion (SPDC) is by modifying the joint spectrum of the photon pairs by means of spectral filters. In this work, we characterize the dependence, with the bandwidth of such filters, of the spectral purity and heralding efficiency of the HSP generated in a bulk SPDC. The values we report for the purity and heralding efficiency are obtained from measurements of the joint spectrum. Our results are in agreement with the theoretical model that predicts a trade-off between the purity and heralding efficiency, and they complement similar measurements that have been done for HSP produced by other types of sources.

中文翻译：

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光谱滤波后的预言单光子的表征

使用自发参量下转换（SPDC）的光学过程时，产生纯先驱单光子（HSP）的一种方法是通过光谱滤光片修改光子对的联合光谱。在这项工作中，我们用这种滤波器的带宽来表征在批量SPDC中生成的HSP的光谱纯度和先驱效率的依赖性。我们报告的纯度和放牧效率值是通过联合光谱的测量得出的。我们的结果与预测纯度和放牧效率之间折衷方案的理论模型相符，并且它们补充了对其他类型来源产生的HSP所做的类似测量。