Directional polarization vortex nanofocusing with a plasmonic lens

Area of Science:

• Photonics and Nanotechnology
• Optics and Light Manipulation

Background:

• Plasmonic lenses focus light to nanoscale dimensions using surface plasmon polaritons.
• Existing plasmonic lenses primarily handle chiral light or phase vortices, neglecting polarization vortices.

Purpose of the Study:

• To introduce a novel plasmonic polarization vortex lens (PPVL) for directional manipulation of polarization vortex beams.
• To achieve two-mode nanofocusing by integrating orthogonal PPVLs.

Main Methods:

• Designing and fabricating plasmonic polarization vortex lenses (PPVLs).
• Combining two orthogonal PPVLs to achieve two-mode nanofocusing.
• Characterizing the focusing performance, including extinction ratio and full width at half-maximum (FWHM).

Main Results:

• Demonstrated directional manipulation of input polarization vortex beams to a designated focus.
• Achieved two-mode nanofocusing with a high extinction ratio.
• Obtained a full width at half-maximum (FWHM) of 0.6–1 µm, indicating nanoscale focusing.

Conclusions:

• The developed PPVL effectively controls polarization vortex beams at the nanoscale.
• This technology can drive applications in on-chip manipulation of polarization vortices.
• The findings expand the utility of plasmonic lenses in integrated optics and photonics.