Exceptional Photon Blockade: Engineering Photon Blockade with Chiral Exceptional Points

Non-Hermitian spectral degeneracies, known as exceptional points (EPs), feature simultaneous coalescence of both eigenvalues and the associated eigenstates a system. A host intriguing EP effects their applications have been revealed in classical realm, such loss-induced lasing, single-mode laser, EP-enhanced sensing. Here we show that purely quantum effect, single-photon blockade, emerges Kerr microring resonator due to EP-induced asymmetric coupling between optical modes nonlinearity-induced anharmonic energy-level spacing. striking this photon blockade is it at two-photon resonance which Hermitian systems will only lead photon-induced tunneling but not blockade. By tuning system towards or away from an EP, one can control correlations, implying potential use our for frequency tunable generation antibunching-to-bunching light switch. Our work sheds new on EP-engineered effects, providing unique opportunities making utilizing various devices.