In this work, we demonstrate the use of two-photon polymerization direct laser writing in the production of continuously tuneable optical vortex beam (OV) generators in a liquid crystal (LC) layer sandwiched between glass substrates. Results are presented that show how an OV generator can be inscribed into a 20 μm-thick LC layer and how the order of the OV beam can be tuned with the application of a voltage. Importantly, only a single pair of electrodes is needed to tune the order of the vortex as the required phase profile is generated through the 3D structuring of the polymer network using the laser writing process. Following the design and fabrication of the LC-OV generator, a Mach–Zehnder interferometer is subsequently employed, in conjunction with polarizing optical microscopy, to characterize the devices to confirm the generation of OVs of different orders and to determine the corresponding chirality. The paper concludes by considering whether these LC-OV generators can function at a range of different operation wavelengths. Such devices would be of potential importance in applications ranging from optical communications to quantum physics.

中文翻译：

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连续可调单电极对液晶光学涡旋发生器

在这项工作中，我们演示了如何使用双光子聚合直接激光写入在夹在玻璃基板之间的液晶（LC）层中生产连续可调光学涡旋光束（OV）发生器。结果显示了如何将 OV 发生器刻入 20 μm 厚的 LC 层，以及如何通过施加电压来调整 OV 光束的阶数。重要的是，由于使用激光写入过程通过聚合物网络的 3D 结构化生成所需的相位分布，因此仅需要一对电极来调整涡流的顺序。在设计和制造 LC-OV 发生器之后，随后使用马赫-曾德干涉仪与偏振光学显微镜结合来表征器件，以确认不同级数 OV 的生成并确定相应的手性。本文最后考虑了这些 LC-OV 发生器是否可以在一系列不同的工作波长下工作。此类设备在从光通信到量子物理的应用中具有潜在的重要性。