Optimizing quantum dot single-photon sources for quantum cryptography

Quantum cryptography relies on quantum mechanics to achieve security beyond classical methods, requiring high-quality single-photon sources. Semiconductor quantum dots (QDs) offer a deterministic, high-brightness alternative with low multiphoton emission, making them strong candidates for secure quantum communication. This talk presents recent theoretical and experimental results from the University of Vienna. We identify optimal QD excitation schemes for cryptographic tasks, benchmarking their performance against Poisson Distributed Sources such as weak coherent states and spontaneous parametric down-conversion. Experimentally, we demonstrate how phonon-assisted excitation enables robust and secure quantum key distribution using QDs emitting in the telecom C-band. Finally, I will hint at ongoing work exploring QDs for cryptographic implementations beyond QKD over deployed fiber links. These findings highlight QDs as a promising platform for a quantum-secure internet.