Intrinsic and extrinsic orbital angular momentum of a self-healed optical vortex

Area of Science:

• Optics
• Quantum Information Science
• Photonics

Background:

• Orbital angular momentum (OAM) of light is crucial for optical communication and quantum information due to its robustness.
• Vortex beams possess intrinsic OAM, a property that can be influenced by external factors.
• Understanding OAM behavior under perturbations is key to advancing optical technologies.

Purpose of the Study:

• To experimentally and theoretically investigate the behavior of OAM in self-healed vortex beams when subjected to spatial obstructions.
• To quantify the generation of extrinsic OAM and its relationship with intrinsic OAM.
• To assess the conservation of OAM components during propagation for potential applications.

Main Methods:

• Experimental measurements of OAM in Laguerre-Gaussian (LG) vortex beams with controlled spatial obstructions (10%-35% intensity clipping).
• Analytical and numerical simulations to model OAM dynamics under obstruction.
• Characterization of both intrinsic and extrinsic OAM components.

Main Results:

• Spatial obstructions break the symmetry of a topological charge 1 LG beam.
• A measurable extrinsic OAM component (up to 0.23 ℏ per photon) is generated.
• The intrinsic OAM (1 ℏ per photon) remains unchanged, and both components are conserved during propagation.

Conclusions:

• Self-healed vortex beams exhibit both intrinsic and extrinsic OAM components that are robust to obstructions.
• The conservation of these OAM components upon propagation highlights their potential for reliable optical communication and quantum information processing.
• This study provides insights into manipulating and preserving OAM for advanced photonic applications.