A meta-prism for high-efficiency coupling between free space and optical waveguides with different angular momentums

¹ College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University - Suzhou 215006, China
² Key Laboratory of Modern Optical Technologies ( Soochow University), Education of Ministry & Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province - Suzhou 215006, China
³ National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University - Nanjing 210093, China

^(a) hcchu92@stu.suda.edu.cn
^(b) laiyun@nju.edu.cn

Received: 11 June 2018
Accepted: 7 August 2018

Abstract

In this work, we design a type of meta-prism which can provide high-efficiency coupling between free space and optical waveguides at infrared frequencies. The meta-prism is composed of an ABA multilayer structure with a fixed total thickness. By varying the filling ratio of the components, the phase of the transmitted wave can be tuned to almost cover the whole range of , while maintaining a robust high transmittance at the same time. Through two examples, we demonstrate the efficient coupling of light into optical waveguides such as metal wires and optical fibers in a noninvasive way. We also demonstrate an approach to generate waveguide modes with different orbital angular momentums. The meta-prism, as a type of compact and efficient optical coupler, may have important applications in nanophotonics and optical communication.