Singh Keshaan, Dudley Angela
School of Physics, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa.
Nanophotonics. 2021 Dec 7;11(4):753-761. doi: 10.1515/nanoph-2021-0484. eCollection 2022 Jan.
Vectorial structured light fields have displayed properties advantageous in many disciplines ranging from communications, microscopy and metrology to laser cutting and characterizing quantum channels. The generation of these fields has been made convenient through the implementation of nanophotonic metasurfaces amongst other static and digital techniques. Consequently, the detection and characterisation of these fields is of equal importance. Most existing techniques involve using separate polarization optics and correlation filters to perform the projective measurements - or are only able to perform such measurements on a subset of possible vector states. We present a compact, fully automated measurement technique based on a digital micro-mirror device (DMD), which facilitates the complete, local and global, characterisation of the spatial mode and polarization degrees-of-freedom (DOFs) for arbitrary vectorial fields. We demonstrate our approach through the identification of relevant hybrid-order Poincaré spheres, the reconstruction of state vectors on these spheres, as well as the recovery of the non-separability and states-of-polarization for a variety of vector beams.
矢量结构光场在从通信、显微镜学、计量学到激光切割以及量子通道表征等众多学科中都展现出了优势特性。通过纳米光子超表面以及其他静态和数字技术的应用，这些光场的产生变得便捷。因此，对这些光场的检测和表征同样重要。大多数现有技术涉及使用单独的偏振光学器件和相关滤波器来进行投影测量——或者仅能够对可能的矢量态的一个子集进行此类测量。我们提出了一种基于数字微镜器件（DMD）的紧凑、全自动测量技术，该技术有助于对任意矢量场的空间模式和偏振自由度（DOF）进行完整、局部和全局的表征。我们通过识别相关的混合阶庞加莱球、在这些球上重建态矢量以及恢复各种矢量光束的不可分离性和偏振态来展示我们的方法。
