Robust photon transmission in nonlinear parity-time-symmetric cavities

TL;DR

This paper demonstrates that nonlinear parity-time-symmetric cavities can achieve robust photon transfer with steady-state saturated gain, overcoming symmetry-breaking issues and outperforming conventional tuning methods.

Contribution

It introduces a nonlinear PT-symmetric cavity system with analytical solutions showing enhanced robustness and efficiency in photon transfer, advancing experimental and theoretical understanding.

Findings

Saturated gain automatically satisfies PT symmetry in steady state.

Photon transmission efficiency remains stable despite coupling variations.

Spontaneous symmetry-breaking occurs in weak coupling regimes.

Abstract

We explore the photon transfer in the nonlinear parity-time-symmetry system of two coupled cavities, which contains nonlinear gain and loss dependent on the intracavity photons. Analytical solution to the steady state gives a saturated gain, which satisfy the parity-time symmetry automatically. The eigen-frequency self-adapts the nonlinear saturated gain to reach the maximum efficiency in the steady state. We find that the saturated gain in the weak coupling regime does not match the loss in the steady state, exhibiting an appearance of a spontaneous symmetry-breaking. The photon transmission efficiency in the parity-time-symmetric regime is robust against the variation of the coupling strength, which improves the results of the conventional methods by tuning the frequency or the coupling strength to maintain optimal efficiency. Our scheme provides an experimental platform for realizing the robust photon transfer in cavities with nonlinear parity-time symmetry.