Achieving Robust Single-Photon Blockade with a Single Nanotip

TL;DR

This paper demonstrates that a nanotip near a Kerr nonlinear resonator can enable robust single-photon blockade, maintaining quantum correlations despite backscattering losses, which is crucial for practical quantum photonic devices.

Contribution

Introducing a nanotip near a Kerr nonlinear resonator to achieve backscattering-immune single-photon blockade, enhancing robustness of quantum devices against imperfections.

Findings

Quantum correlation approaches that of a lossless cavity despite backscattering.

Quantum behavior differs from classical mean-photon number with varying nonlinearity.

The method offers a pathway to robust single-photon sources and quantum devices.

Abstract

Backscattering losses, due to intrinsic imperfections or external perturbations that are unavoidable in optical resonators, can severely affect the performance of practical photonic devices. In particular, for quantum single-photon devices, robust quantum correlations against backscattering losses, which are highly desirable for diverse applications, have remained largely unexplored. Here, we show that single-photon blockade against backscattering loss, an important purely quantum effect, can be achieved by introducing a nanotip near a Kerr nonlinear resonator with intrinsic defects. We find that the quantum correlation of single photons can approach that of a lossless cavity even in the presence of strong backscattering losses. Moreover, the behavior of such quantum correlation is distinct from that of the classical mean-photon number with different strengths of the nonlinearity, due to the interplay of the resonator nonlinearity and the tip-induced optical coupling. Our work sheds new light on protecting and engineering fragile quantum devices against imperfections, for applications in robust single-photon sources and backscattering-immune quantum devices.