Arbitrary orbital angular momentum of photons

TL;DR

This paper introduces a comprehensive method for generating arbitrarily tunable orbital angular momentum (OAM) in photons, extending the concept to vector fields and demonstrating both theoretical and experimental control over this property.

Contribution

It presents the concept of general OAM in vector fields and demonstrates the first controlled creation of arbitrary OAM states both theoretically and experimentally.

Findings

Successfully realized arbitrary OAM in experiments

Arbitrary OAM maintains intrinsic properties of integer OAM

Flexible tailoring of OAM radius enables diverse applications

Abstract

Orbital angular momentum (OAM) of photons, as a new fundamental degree of freedom, has excited a great diversity of interest, because of a variety of emerging applications. Arbitrarily tunable OAM has gained much attention, but its creation remains still a tremendous challenge. We demonstrate the realization of well-controlled arbitrary OAM in both theory and experiment. We present the concept of general OAM, which extends the OAM carried by the scalar vortex field to the OAM carried by the azimuthally varying polarized vector field. The arbitrary OAM has the same characteristics as the well-defined integer OAM: intrinsic OAM, uniform local OAM and intensity ring, and propagation stability. The arbitrary OAM has unique natures: it is allowed to be flexibly tailored and the radius of the focusing ring can have various choices for a desired OAM, which are of great significance to the benefit of surprising applications of the arbitrary OAM.