手性光纤光栅中光轨道角动量的转换。

Conversion of orbital angular momentum of light in chiral fiber gratings.

机构信息

Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027, China.

出版信息

Opt Lett. 2013 Jun 1;38(11):1978-80. doi: 10.1364/OL.38.001978.

DOI:10.1364/OL.38.001978

PMID:23722809

Abstract

We examine mode couplings in chiral fiber grating (CFG) with N-fold rotation symmetry in the cross section and show how the angular momentum matching condition in couplings determines the generation and conversion of orbital angular momentum (OAM) beams. Then we discuss interactions of OAM and spin angular momentum in single- and double-helix long-period CFGs excited by the fundamental core modes. Subsequently, taking right-handed elliptic-core long-period CFGs as example, we demonstrate a dual-OAM converter generating OAM beams with charge +2 and charge +4 at dual wavelengths, both with a conversion efficiency greater than 97%, as well as a broadband converter based on adiabatic coupling, with a bandwidth about 10 nm for a conversion efficiency greater than 95%.

摘要

我们研究了具有 N 重旋转对称性的手性光纤光栅（CFG）中的模式耦合，并展示了耦合中的角动量匹配条件如何决定轨道角动量（OAM）光束的产生和转换。然后，我们讨论了单和双螺旋长周期 CFG 中基本芯模激发的 OAM 和自旋角动量的相互作用。随后，以右手椭圆芯长周期 CFG 为例，我们演示了一个双 OAM 转换器，它可以在双波长下产生 OAM 光束，电荷分别为+2 和+4，转换效率均大于 97%，以及一个基于绝热耦合的宽带转换器，带宽约为 10nm，转换效率大于 95%。