Abstract
Vortex beams were theoretically demonstrated by patterning a fiber facet with $N$-segment microphase plates. By changing the aluminum oxynitride material composition of each segment, gradient refractive-index phase plates (GRPs) were designed and introduced a ${{2}}\pi l$ azimuthal optical phase difference. The gradient index profile was able to convert a fiber Gaussian mode to a Laguerre–Gaussian mode with varieties of topological charge $l$. A three-dimensional finite-difference time-domain method was applied to calculate the near-field optical phase maps and the far-field beam profiles projected from the micro-GRPs. A uniform vortex beam with a symmetrical doughnut shape was obtained by optimizing the GRPs’ radii and the number of segments. The micro-GRPs enabled flat optical components for efficient vortex beam generation.
© 2021 Optical Society of America
Full Article | PDF ArticleMore Like This
William R. Kerridge-Johns, Jean-Benoît Jaillot, and Michael J. Damzen
Appl. Opt. 60(12) 3510-3516 (2021)
W. M. Lee, X.-C. Yuan, and W. C. Cheong
Opt. Lett. 29(15) 1796-1798 (2004)
Zhe Shen, Zhiyuan Xiang, Ziyao Wang, Yaochun Shen, and Baifu Zhang
Appl. Opt. 60(16) 4820-4826 (2021)