# Pure Single Photons from Scalable Frequency Multiplexing

## TL;DR

This paper presents a scalable frequency multiplexing method for generating multiple indistinguishable, pure single photons suitable for quantum information, demonstrating increased single-photon delivery probability without raising multiphoton events.

## Contribution

It introduces a resource-efficient frequency multiplexing scheme for pure single photon generation, enhancing quantum photonic source scalability.

## Key findings

- Multiplexing increases single-photon delivery probability.
- Photon statistics show multiplexing does not increase multiphoton events.
- Interference measurements confirm high single-photon purity.

## Abstract

We demonstrate multiphoton interference using a resource-efficient frequency multiplexing scheme, suitable for quantum information applications that demand multiple indistinguishable and pure single photons. In our source, frequency-correlated photon pairs are generated over a wide range of frequencies by pulsed parametric down conversion. Indistinguishable single photons of a predetermined frequency are prepared using frequency-resolved detection of one photon to control an electro-optic frequency shift applied to its partner. Measured photon statistics show multiplexing increases the probability of delivering a single photon, without a corresponding increase to multiphoton events. Interference of consecutive outputs is used to bound the single-photon purity and demonstrate the non-classical nature of the emitted light.