Optical analogue of the dynamical Casimir effect in a dispersion-oscillating fibre

Stefano Vezzoli,Alexandre Kudlinski,Arnaud Mussot,Niclas Westerberg,Eric Lantz,Daniele Faccio,Angus Prain,Fabio Biancalana,Hatef Dinparasti Saleh

doi:10.1038/s42005-019-0183-z

Abstract

The dynamical Casimir effect is the generation of pairs of real particles or photons from the vacuum as a result of a non-adiabatic change of a system parameter or boundary condition. As opposed to standard parametric amplification where the modulation occurs both in space and in time, this fundamental process requires a pure modulation in time, which makes its detection particularly challenging at optical frequencies. In this paper we experimentally demonstrate a realization of the analogue dynamical Casimir effect in the near-infrared optical regime in a dispersion-oscillating photonic crystal fibre. The experiments are based on the equivalence of the spatial modulation of the fibre core diameter to a pure temporal modulation when this is considered in the co-moving frame of the travelling pump pulse. We provide evidence of optical dynamical Casimir effect by measuring quantum correlations between the spectrally resolved photon pairs and prove their non-classical nature with photon anti-bunching.

Highlights

The dynamical Casimir effect is the generation of pairs of real particles or photons from the vacuum as a result of a non-adiabatic change of a system parameter or boundary condition
The distinguishing physical feature between standard parametric amplification and Dynamical Casimir Effect (DCE) is that the former relies on a polarisation wave propagating in a long medium so the modulation occurs both in space and in time whereas the latter refers to a temporal variation of the medium that is uniform along the longitudinal propagation direction
Our proposal represents an optical analogue of the mechanical DCE in the sense that the mechanical motion of mirrors is replaced by a time modulation of a system parameter, the refractive index

Summary

Introduction

The dynamical Casimir effect is the generation of pairs of real particles or photons from the vacuum as a result of a non-adiabatic change of a system parameter or boundary condition. One of the most outstanding predictions of quantum field theory is that pairs of real particles can be generated from the vacuum as a result of a strong non-adiabatic change of a system parameter or boundary condition[1,2] This is referred to as the Dynamical Casimir Effect (DCE)[1,3,4,5,6] and is usually described as a process in which a cavity with periodically oscillating mirrors produces pairs of photons from the vacuum. The generation of photon pairs by DCE in the optical region, e.g. by nonlinear optical process, has not been demonstrated to date

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