Spontaneous parametric down-conversion (SPDC) is the most widely-used method to generate higher-order Fock states (n≥2). Yet, a consistent performance analysis from fundamental principles is missing. Here we address this problem by introducing a framework for state fidelity and generation probability under the consideration of losses and multimode emission. With this analysis we show the fundamental limitations of this process as well as a trade-off between state fidelity and generation rate intrinsic to the probabilistic nature of the process. This identifies the parameter space for which SPDC is useful when generating higher-order Fock states for quantum applications. We experimentally investigate the strong pump regime of SPDC and demonstrate heralded Fock states up to ∣n⟩=4.
@article{arxiv.1901.03237,
title = {On the scalability of parametric down-conversion for generating higher-order Fock states},
author = {Johannes Tiedau and Tim J. Bartley and Georg Harder and Adriana E. Lita and Sae Woo Nam and Thomas Gerrits and Christine Silberhorn},
journal= {arXiv preprint arXiv:1901.03237},
year = {2019}
}