Quantum-Fluctuation-Initiated Coherence in Multi-Octave Raman Optical Frequency Combs

TL;DR

This paper demonstrates that multi-octave Raman frequency combs generated in a hydrogen-filled fiber exhibit strong coherence despite originating from quantum fluctuations, indicating potential for nonclassical correlations across all lines.

Contribution

It provides experimental and theoretical evidence of quantum-fluctuation-initiated coherence in multi-octave Raman frequency combs, a novel insight into their coherence properties.

Findings

Spectral components show strong self and mutual coherence within each laser pulse.

Coherence arises from quantum zero-point fluctuations despite large phase and energy fluctuations.

Indicates potential for nonclassical correlations between all comb lines.

Abstract

We show experimentally and theoretically that the spectral components of a multi-octave frequency comb spontaneously created by stimulated Raman scattering in a hydrogen-filled hollow-core photonic crystal fiber exhibit strong self coherence and mutual coherence within each 12 ns driving laser pulse. This coherence arises in spite of the field's initiation being from quantum zero-point fluctuations, which causes each spectral component to show large phase and energy fluctuations. This points to the possibility of an optical frequency comb with nonclassical correlations between all comb lines.