Spin-to-orbital angular momentum conversion in focusing, scattering, and imaging systems

Area of Science:

• Optics and Photonics
• Quantum Optics
• Light-Matter Interactions

Background:

• Spin-to-orbital angular momentum (AM) conversion is crucial for manipulating light properties.
• Understanding this conversion in diverse optical systems (focusing, scattering, imaging) is essential for advanced applications.
• Existing theories often lack generality or direct applicability across different optical configurations.

Purpose of the Study:

• To present a unified, general theory for spin-to-orbital angular momentum (AM) conversion of light.
• To provide a framework for calculating and comparing AM conversion efficiency in various optical systems.
• To discuss experimental observations of AM conversion using intensity and polarimetric measurements.

Main Methods:

• Development of a general theory based on universal geometric transformations.
• Application of the theory to non-paraxial optical fields in focusing, scattering, and imaging systems.
• Analysis of AM conversion efficiency through theoretical calculations.

Main Results:

• A universal theoretical framework for spin-to-orbital AM conversion is established.
• The theory allows for direct quantitative prediction and comparison of AM conversion efficiency.
• The framework is validated by discussing observations using local intensity and far-field polarimetry.

Conclusions:

• The presented general theory offers a powerful tool for understanding and predicting spin-to-orbital AM conversion in diverse optical settings.
• This work facilitates the design and optimization of optical systems for applications requiring precise control of light's AM.
• The theory's broad applicability enhances the study of light-matter interactions and optical metrology.