Generation of Fourier transform limited heralded single photons

TL;DR

This paper investigates how to generate heralded single photons with optimal spectral and temporal properties, deriving conditions for purity and Fourier-transform limited states, and identifying source geometries that optimize photon wavepacket duration.

Contribution

It provides specific conditions and source geometries for producing pure, Fourier-transform limited heralded single photons with minimal temporal duration.

Findings

Derived conditions for pure and Fourier-transform limited photons.

Identified source geometries that optimize photon wavepacket duration.

Showed one geometry yields shortest possible heralded photon wavepackets.

Abstract

In this paper we study the spectral (temporal) properties of heralded single photon wavepackets, triggered by the detection of an idler photon in the process of parametric downconversion. The generated single photons are studied within the framework of the chronocyclic Wigner function, from which the single photon spectral width and temporal duration can be computed. We derive specific conditions on the two-photon joint spectral amplitude which result in both pure and Fourier- transform limited heralded single photons. Likewise, we present specific source geometries which lead to the fulfilment of these conditions and show that one of these geometries leads, for a given pump bandwidth, to the temporally shortest possible heralded single photon wavepackets.