Nitrogen-vacancy centres in nanodiamonds (NDs) provide a promising resource for quantum photonic systems. However, developing a technology beyond proof-of-principle physics requires optimally engineering its component parts. In this work, we present a hybrid materials platform by photolithographically positioning ball-milled isotopically-enriched NDs on broadband metal reflectors. The structure enhances the photonic collection efficiency, enabling cryogenic characterisation despite the limited numerical aperture imposed by our cryostat. Our device, with SiO2 above a silver reflector, allows us to perform spectroscopic characterisation at 16 K and measure autocorrelation functions confirming single-photon emission (g2(0)<0.5). Through comparative studies of similar hybrid device configurations, we can move towards optimally engineered techniques for building and analysing quantum emitters in wafer-scale photonic environments.
@article{arxiv.2508.06424,
title = {Single photon emission from lithographically-positioned engineered nanodiamonds for cryogenic applications},
author = {Vivekanand Tiwari and Zhaojin Liu and Hao-Cheng Weng and Krishna C Balram and John G Rarity and Soumen Mandal and Oliver A Williams and Gavin W Morley and Joe A Smith},
journal= {arXiv preprint arXiv:2508.06424},
year = {2025}
}