Comment on "Higher Order Pancharatnam-Berry Phase and the Angular Momentum of Light"

TL;DR

This paper critiques a recent study on the Pancharatnam-Berry phase, clarifying that the spin-orbit converters used do not produce a true path on the higher-order Poincaré sphere, and discusses how to properly acquire the phase.

Contribution

It provides a critical analysis of the previous work and offers insights into correctly obtaining the Pancharatnam-Berry phase with spin-orbit converters.

Findings

SOCs do not generate a path on the HOPS as previously claimed.

Proper acquisition of PBP requires specific trajectory considerations.

Clarification of the relationship between SOCs and the HOPS.

Abstract

In a recent letter, Milione et al. reported the Pancharatnam-Berry phase (PBP) on a higher-order Poincar\'e sphere (HOPS) [Phys. Rev. Lett, 108, 190401 (2012)]. They used two spin-orbit converters (SOCs) to make a trajectory along the HOPS. However, the SOCs actually do not make a path on the HOPS. We briefly discuss a way of acquiring a PBP made by SOCs.