Zhou Yiyu, Mirhosseini Mohammad, Fu Dongzhi, Zhao Jiapeng, Hashemi Rafsanjani Seyed Mohammad, Willner Alan E, Boyd Robert W
The Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
Key Laboratory for Quantum Information and Quantum Optoelectronic Devices, Department of Applied Physics, Xi'an Jiaotong University, Xi'an, Shaanxi Province 710049, China.
Phys Rev Lett. 2017 Dec 29;119(26):263602. doi: 10.1103/PhysRevLett.119.263602. Epub 2017 Dec 28.
The Laguerre-Gaussian (LG) modes constitute a complete basis set for representing the transverse structure of a paraxial photon field in free space. Earlier workers have shown how to construct a device for sorting a photon according to its azimuthal LG mode index, which describes the orbital angular momentum (OAM) carried by the field. In this paper we propose and demonstrate a mode sorter based on the fractional Fourier transform to efficiently decompose the optical field according to its radial profile. We experimentally characterize the performance of our implementation by separating individual radial modes as well as superposition states. The reported scheme can, in principle, achieve unit efficiency and thus can be suitable for applications that involve quantum states of light. This approach can be readily combined with existing OAM mode sorters to provide a complete characterization of the transverse profile of the optical field.
拉盖尔 - 高斯（LG）模式构成了一个完备的基集，用于表示自由空间中傍轴光子场的横向结构。早期的研究人员已经展示了如何构建一种根据光子的方位角LG模式指数对其进行分选的装置，该指数描述了场携带的轨道角动量（OAM）。在本文中，我们提出并演示了一种基于分数傅里叶变换的模式分选器，以根据光场的径向分布有效地分解光场。我们通过分离单个径向模式以及叠加态来实验表征我们实现方案的性能。所报道的方案原则上可以实现单位效率，因此适用于涉及光量子态的应用。这种方法可以很容易地与现有的OAM模式分选器相结合，以提供光场横向分布的完整表征。
