Chiral Interaction Induced Near-Perfect Photon Blockade

TL;DR

This paper theoretically demonstrates that chiral interactions in waveguide-cavity QED systems can induce near-perfect photon blockade through multi-photon interference, with robustness and parity-dependent output states, advancing single-photon source development.

Contribution

It introduces a novel mechanism for photon blockade using chiral interactions and analyzes the effects of multiple cavities on the blockade efficiency and output states.

Findings

Near-perfect photon blockade achieved via chiral interaction.

Optimal parameters decrease exponentially with more cavities.

Output state parity depends on the number of cavities.

Abstract

Based on the scattering matrix method, we theoretically demonstrate that the chiral interaction can induce the almost perfect photon blockade (PB) in the waveguide-cavity quantum electrodynamics (QED) system. The mechanism relies on the multi-photon paths interference within the waveguide, which is clearly shown by the analytic parameter regime for $g^{(2)}(0)\approx0$. When $N$ cavities are introduced into the system, there are $N$ optimal parameter points accordingly for the almost perfect PB, where the required lowest chirality decreases exponentially with increasing $N$, and these optimal points are robust against disorder in the system's frequencies. Under resonant driving and fixed chirality conditions, the output light depends solely on the parity of $N$ ($N\ge2$), with a coherent state emerging for even numbers of cavities and a single-photon state for odd numbers. Our work offers an alternative route for achieving almost perfect PB effects with high single-photon transmission by employing the chirality of system, with potential application in the on-chip single-photon source with integrability.