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Mapping the spin angular momentum distribution of focused linearly and circularly polarized vortex fields
Applied Optics
|February 24, 2022
Summary
Researchers mapped spin angular momentum (SAM) distributions in focused light beams using spin-resolved near-field scanning optical microscopy (NSOM). This technique precisely visualizes SAM components, crucial for advancing spin optics and topological photonics research.
Area of Science:
- Optics and Photonics
- Quantum Optics
- Nanotechnology
Background:
- Spin angular momentum (SAM) is critical for understanding light-matter interactions.
- Previous work established the utility of spin-resolved near-field scanning optical microscopy (NSOM) for mapping vector vortex beams.
- Accurate mapping of SAM in focused vortex beams is essential for near-field spin optics and topological photonics.
Purpose of the Study:
- To map the spin angular momentum (SAM) axial component (Sz) distributions of tightly focused linearly and circularly polarized vortex beams.
- To demonstrate the capability of the spin-resolved NSOM technique for analyzing complex polarized light fields.
- To provide foundational data for research in near-field spin optics and topological photonics.
Main Methods:
- Utilized a previously developed spin-resolved near-field scanning optical microscopy (NSOM) system.
- Mapped the distributions of right spin (I+) and left spin (I-) components of focused vortex beams.
- Calculated the SAM axial component (Sz) using the relationship Sz ∝ I+ - I-.
Main Results:
- Successfully mapped the SAM axial component (Sz) distributions for various orders of focused linearly and circularly polarized vortex beams.
- Confirmed the effectiveness of the spin-resolved NSOM technique for analyzing SAM in complex optical fields.
- Provided detailed spatial distributions of SAM for different types of focused vortex beams.
Conclusions:
- The spin-resolved NSOM technique is effective for mapping SAM distributions in focused vortex beams.
- The ability to resolve spin components is vital for advancing research in spin optics and topological photonics.
- This study provides essential insights into the spin properties of focused light fields.
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