Classical analogues of two-photon quantum interference

TL;DR

This paper demonstrates classical analogues of quantum two-photon interference effects using chirped-pulse interferometry, revealing new phenomena like phase super-resolution and extended coherence lengths.

Contribution

It introduces modified CPI setups that replicate quantum HOM interference effects and achieve phase super-resolution with longer coherence lengths.

Findings

Observation of classical HOM peak analogue

Detection of quantum beating analogue

Generation of phase super-resolution with extended coherence length

Abstract

Chirped-pulse interferometry (CPI) captures the metrological advantages of quantum Hong-Ou-Mandel (HOM) interferometry in a completely classical system. Modified HOM interferometers are the basis for a number of seminal quantum-interference effects. Here, the corresponding modifications to CPI allow for the first observation of classical analogues to the HOM peak and quantum beating. They also allow a new classical technique for generating phase super-resolution exhibiting a coherence length dramatically longer than that of the laser light, analogous to increased two-photon coherence lengths in entangled states.