Towards quantum frequency combs: boosting the generation of highly nonclassical light states by cavity-enhanced parametric down-conversion at high repetition rates

TL;DR

This paper presents a method for generating multi-photon quantum states using cavity-enhanced parametric down-conversion at high repetition rates, advancing quantum optics and quantum information applications.

Contribution

The authors demonstrate cavity-enhanced parametric down-conversion in a high-repetition-rate pulsed regime, enabling efficient generation of nonclassical light states with preserved comb structure.

Findings

Enhanced parametric gain via an external cavity

Successful generation and tomography of two-photon Fock states

Potential for integrating quantum and comb technologies

Abstract

We demonstrate the generation of multi-photon quantum states of light by cavity-enhanced parametric down-conversion in the high-repetition-rate pulsed regime. An external enhancement cavity resonant with the spectral comb of modes of a mode-locked pump laser provides a coherent build-up of the pump intensity and greatly enhances the parametric gain without sacrificing its high repetition rate and comb structure. We probe the parametric gain enhancement by the conditional generation and tomographic analysis of two-photon Fock states. Besides its potential impact to efficiently generate highly-nonclassical or entangled multi-photon states in many existing experimental setups, this scheme opens new and exciting perspectives towards the combination of quantum and comb technologies for enhanced measurements and advanced quantum computation protocols.