Generation of Pure-State Single-Photon Wavepackets by Conditional Preparation Based on Spontaneous Parametric Downconversion

TL;DR

This paper explores how to generate pure single-photon wavepackets using spontaneous parametric downconversion, focusing on conditions for purity and experimental methods to optimize single-photon preparation.

Contribution

It derives modal conditions for pure single-photon states and proposes experimental techniques to produce ideal photon pairs for conditional preparation.

Findings

Derived conditions for modal characteristics ensuring photon purity

Proposed experimental techniques for optimal photon pair generation

Identified criteria for achieving quantum-mechanically pure single photons

Abstract

We study the conditional preparation of single photons based on parametric downconversion, where the detection of one photon from a given pair heralds the existence of a single photon in the conjugate mode. We derive conditions on the modal characteristics of the photon pairs, which ensure that the conditionally prepared single photons are quantum-mechanically pure. We propose specific experimental techniques that yield photon pairs ideally suited for single-photon conditional preparation.