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Published on: August 12, 2013
Angular momentum decomposition of nonparaxial light beams
R Martínez-Herrero1, P M Mejías
1Departamento de Optica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040-Madrid, Spain.
Optics Express
|July 1, 2010
Summary
This study decomposes the angular momentum of non-paraxial beams into orbital and polarization components. These findings simplify to the familiar orbital and spin components in the paraxial limit, advancing optical physics research.
Area of Science:
- Optics and Photonics
- Electromagnetism
Background:
- Understanding the angular momentum of light is crucial in various optical applications.
- General non-paraxial beams exhibit complex angular momentum properties beyond the paraxial approximation.
Purpose of the Study:
- To decompose the total angular momentum per unit length of a general non-paraxial beam.
- To provide expressions for linear momentum and energy per unit length.
- To demonstrate the recovery of the paraxial limit's orbital and spin components.
Main Methods:
- Decomposition of total angular momentum into orbital and polarization-dependent components.
- Analysis of the spiral spectrum at the far field.
- Examination of the balance between right- and left-handed circular polarization within the angular spectrum.
Main Results:
- The total angular momentum is resolved into an orbital part (linked to the far-field spiral spectrum) and a polarization-dependent part.
- Expressions for linear momentum and energy per unit length are derived.
- The paraxial limit correctly yields the established orbital and spin angular momentum components.
Conclusions:
- The proposed decomposition provides a comprehensive framework for analyzing angular momentum in non-paraxial beams.
- This work bridges the understanding between general optical beams and their paraxial approximations.
- The findings have implications for advanced optical manipulation and information transfer.
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