On-Chip Spin-Orbit Controlled Excitation of Quantum Emitters Coupled to Hybrid Plasmonic Nanocircuits

TL;DR

This paper demonstrates on-chip spin-orbit controlled excitation of quantum emitters using a hybrid plasmonic nanocircuit, enabling unidirectional routing and selective excitation of spatially separated quantum dots for advanced quantum nanophotonics.

Contribution

It introduces a dielectric-loaded plasmonic nanocircuit with an achiral spin-orbit coupler for controlled, unidirectional excitation of quantum emitters on-chip, advancing integrated quantum photonic technologies.

Findings

Circular-polarization controls coupling into waveguides

Quantum dots are excited at ~10 μm apart

Efficient coupling of nitrogen vacancy centers achieved

Abstract

On-chip realization of complex photonic functionalities is essential for further progress in planar integrated nanophotonics, especially when involving nonclassical light sources such as quantum emitters (QEs). Hybrid plasmonic nanocircuits integrated with QEs have been attracting considerable attention due to the prospects of significantly enhancing QE emission rates and miniaturizing quantum nanophotonic components. Spin-orbit interactions on subwavelength scales have been increasingly explored in both conventional and quantum nanophotonics for realization and utilization of the spin-dependent flow of light. Here, we propose and realize a dielectric-loaded plasmonic nanocircuit consisting of an achiral spin-orbit coupler for unidirectional routing of pump radiation into branched QE-integrated waveguides. We demonstrate experimentally the circular-polarization controlled coupling of 532-nm pump laser light into polymer-loaded branched waveguides followed by the excitation of spatially separated (by a distance of ~ 10 {\mu}m) QEs, nanodiamonds, with multiple nitrogen vacancy centres, that are embedded in and efficiently coupled to the corresponding waveguides. The realization of on-chip spin-orbit controlled excitation of different QEs coupled to branched waveguides opens new avenues for designing complex quantum plasmonic nanocircuits exploiting the spin degree of freedom within chiral quantum nanophotonics.