Generation of photonic orbital angular momentum superposition states using vortex beam emitters with superimposed gratings

Qingsheng Xiao,Charalambos Klitis,Shimao Li,Marc Sorel,Xinlun Cai,Yueyang Chen,Siyuan Yu

doi:10.1364/oe.24.003168

Abstract

An integrated approach to produce photonic orbital angular momentum (OAM) superposition states with arbitrary OAM spectrum has been demonstrated. Superposition states between two vector OAM modes have been achieved by integrating a superimposed angular grating in one silicon micro-ring resonator, with each mode having near equal weight. The topological charge difference between the two compositional OAM modes is determined by the difference between the numbers of elements in the two original gratings being superimposed, while the absolute values of the topological charge can be changed synchronously by switching WGM resonant wavelengths. This novel approach provides a scalable and flexible source for the OAM-based quantum information and optical manipulation applications.

Highlights

Orbital angular momentum (OAM) of photons, discovered in 1992, represents an additional intrinsic degree of freedom of a light beam or a single photon, in addition to the ones widely exploited in current photonic technologies [1,2]
Superposition states between two vector orbital angular momentum (OAM) modes have been achieved by integrating a superimposed angular grating in one silicon micro-ring resonator, with each mode having near equal weight
The topological charge difference between the two compositional OAM modes is determined by the difference between the numbers of elements in the two original gratings being superimposed, while the absolute values of the topological charge can be changed synchronously by switching whispering gallery modes (WGMs) resonant wavelengths

Summary

Introduction

Orbital angular momentum (OAM) of photons, discovered in 1992, represents an additional intrinsic degree of freedom of a light beam or a single photon, in addition to the ones (e.g. polarization) widely exploited in current photonic technologies [1,2]. Different from this azimuthal grating coupling mechanism, several approaches such as waveguide-array-based radial grating coupling device [12,13], hybrid 3D PIC device [14], organic semiconductor microdisk laser [15] and micro-scale Spiral Phase Plate integrated VCSEL [16] have been demonstrated readily OAM generating and (de-) multiplexing (multiple OAM states superposition) functions. The relative weight of the OAM states can be varied by varying the size of the grating elements

Concepts and structures

Characterization and results

Conclusion and discussion