Broadening the bandwidth of entangled photons: a step towards the generation of extremely short biphotons

TL;DR

This paper presents a technique to control the bandwidth of entangled photons independently, enabling the generation of nearly transform-limited biphotons with extremely broad bandwidths suitable for attosecond quantum optics.

Contribution

A novel method for independently controlling entangled photon bandwidths, achieving nearly transform-limited biphotons with octave-spanning bandwidths.

Findings

Generated biphotons with nearly one octave bandwidth

Achieved correlation times of a few femtoseconds

Enabled high entanglement degree in photon pairs

Abstract

We demonstrate a technique that allows to fully control the bandwidth of entangled photons independently of the frequency band of interest and of the nonlinear crystal. We show that this technique allows to generate nearly transform-limited biphotons with almost one octave of bandwidth (hundreds of THz) which corresponds to correlation times of just a few femtoseconds. The presented method becomes an enabling tool for attosecond entangled-photons quantum optics. The technique can also be used to generate paired photons with a very high degree of entanglement.