Near-Field Observation of the Photonic Spin Hall Effect

Area of Science:

• Photonics
• Plasmonics
• Nanophotonics

Background:

• The photonic spin Hall effect (PSHE) describes the spin-dependent spatial separation of photons.
• Spin-orbit interactions are key to PSHE, enabling spin-sensitive applications.
• Plasmonic circuits offer a platform for manipulating light at the nanoscale.

Purpose of the Study:

• To investigate spin-orbit interactions in a plasmonic circuit using a subwavelength semiring antenna.
• To demonstrate the unidirectional excitation of surface plasmon polaritons (SPPs) via PSHE.
• To provide insights into the generation and characterization of PSHE in nanophotonic systems.

Main Methods:

• Utilized scattering-type near-field scanning optical microscopy (s-NSOM).
• Employed a subwavelength semiring antenna integrated into a plasmonic circuit.
• Analyzed amplitude- and phase-resolved near-field maps under opposite spin photon excitation.

Main Results:

• Observed clear evidence of spin-orbit interactions induced by the semiring antenna.
• Demonstrated unidirectional excitation of SPPs through spin-dependent coupling.
• Characterized the spatial variation of complex electromagnetic fields in the plasmonic nanocircuit.

Conclusions:

• The study successfully demonstrates the photonic spin Hall effect in a plasmonic nanocircuit.
• The semiring antenna design facilitates spin-selective excitation of SPPs.
• Findings contribute to the development of spin-selective nanophotonic systems and integrated circuits.