Polarization-Engineered Near-Field Generation Using a Hybrid Tip-Antenna System

Area of Science:

• Nanophotonics
• Plasmonics
• Optical Metrology

Background:

• Precise nanoscale light polarization control is essential for chiral optical responses and spin-photon interactions.
• Conventional near-field probes lack control over polarization state and phase.

Purpose of the Study:

• To introduce a novel polarization-engineered near-field methodology for nanoscale light manipulation.
• To demonstrate the generation of circularly polarized nano-light using a combined tip-antenna system.

Main Methods:

• Utilized full-wave electromagnetic simulations to model a combined metallic tip and planar dipole nanoantenna system.
• Investigated the influence of tip-antenna geometry and tip height on field components and phase offset.

Main Results:

• The tip acts as a vertical plasmonic resonator, and the antenna supports an in-plane dipolar mode.
• Achieved comparable amplitudes and a controllable ~90° phase offset between orthogonal field components.
• Generated circularly polarized nano-light in the antenna gap, functioning as a nanoscale quarter-wave plate.

Conclusions:

• The proposed system enables the conversion of linearly polarized light into circularly polarized hotspots without external optics.
• Establishes an experimentally accessible route for polarization-programmable near-field nanoscopy.
• Facilitates chiral spectroscopy, spin/valley physics, and nanoscale quantum optical investigations.