Spin-Exchange-Controlled Nonclassical Light in Cavity Electromagnetically Induced Transparency

arXiv:2611.07382v1 Announce Type: new Abstract: Controlling nonclassical light while maintaining a finite cavity response requires selective suppression of unwanted multiphoton excitation. We investigate a ring-cavity system containing two three-level emitters coupled by a coherent spin-exchange interaction, where electromagnetically induced transparency (EIT) provides resonant access to a dark-state polariton. The exchange interaction shifts the polariton resonance while modifying the dressed two-photon excitation pathways. Strong photon antibunching emerges when the one-polariton resonance nearly coincides with a destructive-interference minimum of the second-photon transition amplitude.