A time/frequency quantum analysis of the light generated by synchronously pumped optical parametric oscillators

TL;DR

This paper develops a comprehensive quantum model for SPOPO-generated light, revealing new properties like CEO phase-related quantum correlations and providing insights into quantum limits for ultra-short time delay measurements.

Contribution

The paper introduces a time/frequency symmetric quantum model for SPOPOs, uncovering novel quantum properties and correlations relevant to real experimental conditions.

Findings

Discovery of quadrature entanglement between frequency combs with opposite CEO phases

Quantum correlations between individual pulses and neighboring pulses

Quantum Cramer-Rao limit for ultra-short time delay measurement

Abstract

We present in this paper a general model for determining the quantum properties of the light generated by a synchronously pumped optical parametric oscillator (SPOPO) operating below threshold. This model considers time and frequency on an equal footing, which allows us to find new quantum properties, related for example to the carrier envelope offset (CEO) phase, and to consider situations that are close to real experiments. We show that, in addition to multimode squeezing in the so-called 'supermodes', the system exhibits quadrature entanglement between frequency combs of opposite CEO phases. We have also determined the quantum properties of the individual pulses and their quantum correlations with the neighboring pulses. Finally, we determine the quantum Cramer-Rao limit for an ultra-short time delay measurement using a given number of pulses generated by the SPOPO.