• Chinese Optics Letters
  • Vol. 20, Issue 2, 023801 (2022)
Chenchu Zhang1、*, Hanchang Ye1, Rui Cao2, Shengyun Ji3, Heng Zhang1, Linhan Zhao1, Sizhu Wu1、**, and Hua Zhai1
Author Affiliations
  • 1Anhui Province Key Laboratory of Aerospace Structural Parts Forming Technology and Equipment, Institute of Industry and Equipment Technology, Hefei University of Technology, Hefei 230009, China
  • 2Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
  • 3Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
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    Abstract

    A ring-shaped focus, such as a focused vortex beam, has played an important role in microfabrication and optical tweezers. The shape and diameter of the ring-shaped focus can be easily adjusted by the topological charge of the vortex. However, the flow energy is also related to the topological charge, making the individual control of diameter and flow energy of the vortex beam impossible. Meanwhile, the shape of the focus of the vortex beam remains in the hollow ring. Expanding the shape of focus of structural light broadens the applications of the vortex beam in the field of microfabrication. Here, we proposed a ring-shaped focus with controllable gaps by multiplexing the vortex beam and annular beam. The multiplexed beam has several advantages, such as the diameter and flow energy of the focal point can be individually controlled and are not affected by the zero-order beam, and the gap size and position are controllable.

    1. Introduction

    A ring-shaped focus with a uniform hollow light distribution has an important role in the fields of optical tweezers [1], microfabrication[2], and communication[3]. In the area of two-photon polymerization (TPP) fabrication, applying the ring-shaped focus instead of the conventional single-point focus allows polymerizing a tubular structure in a single exposure, which greatly improves the fabrication efficiency compared to the point-to-point scanning strategy. Until now, some very specific distributions, including Bessel beams[4], spatially shifted vortex beams[5], double-helix beams[6], and ring-shaped beams[7], have been explored for parallelization of the direct laser writing or even single-shot microfabrication. Among these methods, Bessel beams[8] and vortex beams[9,10] have been widely applied to generate ring-shaped foci. With the flexible control of parameters of Bessel and vortex beams, the diameter of ring-shaped focus can be easily adjusted. By changing the polarization state of an incident light, switchable spatial arrangement of the donut-shaped focusing beams through an engineered microsphere can be tuned[11]. More than that, triangle and rectangle hollow foci can be also achieved by combining the Bessel beam and vortex beam[12], and an ellipse donut focus can be generated by cross phase[13].

    Copy Citation Text
    Chenchu Zhang, Hanchang Ye, Rui Cao, Shengyun Ji, Heng Zhang, Linhan Zhao, Sizhu Wu, Hua Zhai. Rapid fabrication of microrings with complex cross section using annular vortex beams[J]. Chinese Optics Letters, 2022, 20(2): 023801
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    Category: Light-matter Interaction
    Received: Jul. 28, 2021
    Accepted: Aug. 31, 2021
    Published Online: Oct. 18, 2021
    The Author Email: Chenchu Zhang (hfutzcc@hfut.edu.cn), Sizhu Wu (sizhuwu@hfut.edu.cn)