The high-NA focusing properties of vector vortex beams are studied theoretically and experimentally. The vector vortex beams are generated by space-variant segmented subwavelength metallic gratings first. Then the mathematical expressions for the focused fields are derived based on the vector diffraction theory, and some numerical simulations are presented that show that the focused fields are not dark at the center and the focusing spot size of vector vortex beams with high topological charges approaches the diffraction limitation at high NA. Finally, to verify the theoretical analysis, the tightly focused fields are measured based on a confocal microscopy system when the NA of the objective lens is 0.90. The research results confirm the potential of vector vortex beams in some applications, such as optical trapping, laser printing, lithography, and material processing.
© 2011 Optical Society of America
Original Manuscript: July 1, 2011
Revised Manuscript: August 23, 2011
Manuscript Accepted: September 1, 2011
Published: October 17, 2011
Vol. 7, Iss. 1 Virtual Journal for Biomedical Optics
Zhehai Zhou, Qiaofeng Tan, and Guofan Jin, "Theoretical and experimental studies on tightly focused vector vortex beams," Appl. Opt. 50, G80-G85 (2011)