Single Quantum Emitters with Arbitrarily Polarized Dipole Moments Under Ambient Conditions

Abstract

AbstractThe ability to control the spin of dipole moments of single quantum emitters is crucial for spin‐based quantum technologies. However, realizing circularly polarized (CP) dipole moments under ambient conditions has remained an outstanding challenge. Here, this work proposes an optical interface capable of converting a single quantum emitter into a deep‐subwavelength super‐emitter with an arbitrarily polarized dipole moment, including the long‐sought CP dipole. It is accomplished by coupling the emitter to dual dipolar modes of a plasmonic nanoantenna with precisely controlled amplitudes and phases, resulting in a coherent superposition of the modes that generates the desired dipole polarization. Meanwhile, the dipole moment amplitude is enhanced by over an order of magnitude. The CP super‐emitter behaves analogously to an ideal CP point dipole emitter, exhibiting characteristic spiraling field pattern and spin‐directional coupling to waveguide modes due to spin‐orbit locking. The results overcome a long‐standing challenge in constructing spin‐controlled quantum emitters under ambient conditions, opening new possibilities for tailoring light–matter interactions and designing novel quantum optical devices.