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Published on: October 23, 2018
Theoretical and experimental studies on tightly focused vector vortex beams.
Zhehai Zhou1, Qiaofeng Tan, Guofan Jin
1Department of Optical Information Science and Technology, Beijing Information Science and Technology University, Beijing 100192, China. zhouzhehai@tsinghua.org.cn
Applied Optics
|November 17, 2011
Summary
Vector vortex beams exhibit non-dark centers and near-diffraction-limited focusing spots at high numerical aperture (NA). These properties highlight their potential for advanced optical applications like trapping and lithography.
Area of Science:
- Optics and Photonics
- Electromagnetism
- Nanotechnology
Background:
- Vector vortex beams (VVBs) offer unique polarization and phase properties.
- Understanding their focusing behavior is crucial for advanced optical applications.
Purpose of the Study:
- To investigate the high numerical aperture (NA) focusing characteristics of VVBs.
- To theoretically and experimentally validate the focusing performance of VVBs.
Main Methods:
- Generation of VVBs using space-variant segmented subwavelength metallic gratings.
- Derivation of mathematical expressions for focused fields using vector diffraction theory.
- Numerical simulations and experimental verification using confocal microscopy (NA = 0.90).
Main Results:
- Focused fields of VVBs are not dark at the center.
- Focusing spot size approaches the diffraction limit for high topological charges at high NA.
- Experimental measurements confirm theoretical predictions.
Conclusions:
- VVBs demonstrate promising high-NA focusing capabilities.
- The study confirms the potential of VVBs for applications in optical trapping, laser printing, lithography, and material processing.