# Direct Excitation of a Single Quantum Dot with Cavity-SPDC Photons

## TL;DR

This paper demonstrates a novel single-photon source with narrow spectral bandwidth that can directly excite a quantum dot, advancing quantum network interfaces by enabling efficient quantum dot coupling.

## Contribution

The work introduces a mode-engineered cavity-SPDC photon source capable of resonant excitation of quantum dots, a significant step for quantum networking applications.

## Key findings

- Generated sub-GHz bandwidth single photons resonant with quantum dots
- Successfully resonantly excited an isolated quantum dot using the source
- Demonstrated direct coupling between the photon source and quantum dot

## Abstract

The ability to generate mode-engineered single photons to interface with disparate quantum systems is of importance for building a quantum network. Here we report on the generation of a pulsed, heralded single photon source with a sub-GHz spectral bandwidth that couples to indium arsenide quantum dots centered at 942 nm. The source is built with a type-II PPKTP down-conversion crystal embedded in a semi-confocal optical cavity and pumped with a 76 MHz repetition rate pulsed laser to emit collinear, polarization-correlated photon pairs resonant with a single quantum dot. In order to demonstrate direct coupling, we use the mode-engineered cavity-SPDC single-photon source to resonantly excite an isolated single quantum dot.

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Source: https://tomesphere.com/paper/1812.07165