Non-Dissipative Non-Hermitian Dynamics and Exceptional Points in Coupled Optical Parametric Oscillators

TL;DR

This paper introduces non-Hermitian dynamics in coupled optical parametric oscillators (OPOs), highlighting their advantages and novel phenomena like exceptional points, with potential applications in sensing and quantum information.

Contribution

It presents the first detailed analysis of non-Hermitian dynamics in coupled OPOs, including spectral anti-PT symmetry and higher-order exceptional points, surpassing traditional gain-loss systems.

Findings

Coupled OPOs exhibit spectral anti-PT symmetry and exceptional points.

Demonstration of higher-order and Floquet exceptional points in OPO systems.

Generation of squeezed vacuum around exceptional points.

Abstract

Engineered non-Hermitian systems featuring exceptional points can lead to a host of extraordinary phenomena in diverse fields ranging from photonics, acoustics, opto-mechanics, electronics, to atomic physics. Here we introduce and present non-Hermitian dynamics of coupled optical parametric oscillators (OPOs) arising from phase-sensitive amplification and de-amplification, and show their distinct advantages over conventional non-Hermitian systems relying on laser gain and loss. OPO-based non-Hermitian systems can benefit from the instantaneous nature of the parametric gain, noiseless phase-sensitive amplification, and rich quantum and classical nonlinear dynamics. We show that two coupled OPOs can exhibit spectral anti-PT symmetry and an exceptional point between its degenerate and non-degenerate operation regimes. To demonstrate the distinct potentials of the coupled OPO system compared to conventional non-Hermitian systems, we present higher-order exceptional points with two OPOs, tunable Floquet exceptional points in a reconfigurable dynamic non-Hermitian system, and generation of squeezed vacuum around exceptional points, all of which are not easy to realize in other non-Hermitian platforms. Our results show that coupled OPOs are an outstanding non-Hermitian setting with unprecedented opportunities in realizing nonlinear dynamical systems for enhanced sensing and quantum information processing.