# On-demand semiconductor source of entangled photons which simultaneously has high fidelity, efficiency, and indistinguishability

## TL;DR

This paper presents a high-performance, on-demand entangled photon source using a quantum dot-cavity system that achieves high fidelity, efficiency, and indistinguishability simultaneously, advancing quantum photonic technology.

## Contribution

The work demonstrates a quantum dot-based entangled photon source with record-high fidelity, efficiency, and indistinguishability achieved simultaneously using coherent two-photon excitation.

## Key findings

- Entangled photon pairs with 0.90 fidelity
- Pair generation rate of 0.59
- Extraction efficiency of 0.62

## Abstract

An outstanding goal in quantum optics and scalable photonic quantum technology is to develop a source that each time emits one and only one entangled photon pair with simultaneously high entanglement fidelity, extraction efficiency, and photon indistinguishability. By coherent two-photon excitation of a single InGaAs quantum dot coupled to a circular Bragg grating bullseye cavity with broadband high Purcell factor up to 11.3, we generate entangled photon pairs with a state fidelity of 0.90(1), pair generation rate of 0.59(1), pair extraction efficiency of 0.62(6), and photon indistinguishability of 0.90(1) simultaneously. Our work will open up many applications in high-efficiency multi-photon experiments and solid-state quantum repeaters.