Laboratoire Kastler Brossel, Université Pierre et Marie Curie, Ecole Normale Supérieure, CNRS, 4 Place Jussieu, 75252 Paris Cedex 05, France.
Phys Rev Lett. 2013 Nov 22;111(21):213602. doi: 10.1103/PhysRevLett.111.213602. Epub 2013 Nov 19.
The characterization or subsequent use of a propagating optical quantum state requires the knowledge of its precise temporal mode. Defining this mode structure very often relies on a detailed a priori knowledge of the used resources, when available, and can additionally call for an involved theoretical modeling. In contrast, here we report on a practical method enabling us to infer the optimal temporal mode directly from experimental data acquired via homodyne detection, without any assumptions on the state. The approach is based on a multimode analysis using eigenfunction expansion of the autocorrelation function. This capability is illustrated by experimental data from the preparation of Fock states and coherent state superposition.
对传播光量子态的特征描述或后续使用需要精确的时间模式知识。定义此模式结构通常需要在可用时依赖于对所使用资源的详细先验知识，并且可能还需要涉及理论建模。相比之下，在这里我们报告了一种实用的方法，使我们能够直接从通过外差探测获得的实验数据中推断出最佳时间模式，而无需对状态做出任何假设。该方法基于自相关函数的本征函数展开的多模分析。通过从 Fock 态和相干态叠加的制备中获得的实验数据说明了这种能力。
