Noncritical generation of nonclassical frequency combs via spontaneous rotational symmetry breaking

TL;DR

This paper demonstrates that synchronously pumped optical parametric oscillators can spontaneously break symmetry to produce highly nonclassical, perfectly squeezed light modes, offering new insights into dissipative phase transitions and quantum light sources.

Contribution

It reveals the ability of SPOPOs to access symmetry-breaking regimes, enabling robust generation of nonclassical light with potential quantum technology applications.

Findings

Spontaneous symmetry breaking occurs in SPOPOs.

A specific spatiotemporal mode with perfect squeezing is identified.

SPOPOs can generate nonclassical light above threshold.

Abstract

Synchronously pumped optical parametric oscillators (SPOPOs) are optical cavities containing a nonlinear crystal capable of down-converting a frequency comb to lower frequencies. These have received a lot of attention lately, because their intrinsic multimode nature makes them compact sources of quantum correlated light with promising applications in modern quantum information technologies. In this work we show that SPOPOs are also capable of accessing the challenging but interesting regime where spontaneous symmetry breaking plays a crucial role in the quantum properties of the emitted light, difficult to access with any other nonlinear optical cavity. Apart from opening the possibility of studying experimentally this elusive regime of dissipative phase transitions, our predictions will have a practical impact, since we show that spontaneous symmetry breaking provides a specific spatiotemporal mode with perfect squeezing for any value of the system parameters, turning SPOPOs into robust sources of highly nonclassical light above threshold.