Polarization-controlled evolution of light transverse modes and associated Pancharatnam geometric phase in orbital angular momentum

TL;DR

This paper introduces a rapid, efficient method to generate specific orbital angular momentum states of light using a liquid crystal device and interferometer, enabling control over geometric phase transfer.

Contribution

The work demonstrates a novel, high-efficiency technique for creating arbitrary superpositions of orbital angular momentum states with precise phase control.

Findings

Achieved near 100% generation efficiency of OAM states

Controlled transfer of Pancharatnam geometric phase to OAM states

Enabled arbitrary linear combinations of b1 2 OAM eigenstates

Abstract

We present an easy, efficient and fast method to generate arbitrary linear combinations of light orbital angular momentum eigenstates $\ell=\pm 2$ starting from a linearly polarized TEM$_{00}$ laser beam. The method exploits the spin-to-orbital angular momentum conversion capability of a liquid-crystal-based $q$-plate and a Dove prism inserted in a Sagnac polarizing interferometer. The nominal generation efficiency is 100\%, being limited only by reflection and scattering losses in the optical components. When closed paths are followed on the polarization Poincar\'{e} sphere of the input beam, the associated Pancharatnam geometric phase is transferred unchanged to the orbital angular momentum state of the output beam.