Generalized Poincar\'e Sphere

TL;DR

This paper introduces a generalized Poincaré sphere (G sphere) that unifies the geometric representation of various vector fields, extending the standard model to include ellipticity and higher-order angular momentum.

Contribution

The G sphere extends the traditional Poincaré sphere by incorporating continuous ellipticity and higher-dimensional orbital angular momentum, providing a more comprehensive geometric framework.

Findings

Unified geometric representation of vector fields

Inclusion of ellipticity and higher-order OAM

Flexible scheme for generating vector fields

Abstract

We present a generalized Poincar\'e sphere (G sphere) and generalized Stokes parameters (G parameters), as a geometric representation, which unifies the descriptors of a variety of vector fields. Unlike the standard Poincar\'e sphere, the radial dimension in the G sphere is not used to describe the partially polarized field. The G sphere is constructed by extending the basic Jones vector basis to the general vector basis with the continuously changeable ellipticity (spin angular momentum, SAM) and the higher dimensional orbital angular momentum (OAM). The north and south poles of different spherical shell in the G sphere represent the pair of different orthogonal vector basis with different ellipticity (SAM) and the opposite OAM. The higher-order Poincar\'e spheres are just the two special spherical shells of the G sphere. We present a quite flexible scheme, which can generate all the vector fields described in the G sphere. The salient properties of this representation are able to treat the complicated geometric phase of arbitrary vector fields in the future.