Microwave dielectric properties of LiNbO3 and AlN at millikelvin temperatures and single-photon power
Abstract
Efficient bidirectional microwave-optical photon conversion is a key capability for scaling superconducting quantum processors into distributed networks. However, achieving the necessary conversion efficiency requires filling a critical knowledge gap in understanding the loss mechanisms of electro-optic materials. Here, we characterize the microwave properties of single-crystal bulk LiNbO3 and AlN over a broad range of powers, down to single-photon levels, and spanning from millikelvin temperatures to above 1 K. We demonstrate that both materials exhibit two-level systems (TLS) behavior, while piezoelectric-related losses are excluded. We show that TLS-induced dissipation is predominantly localized on the surface rather than being an intrinsic bulk property, a result further corroborated by room-temperature 3D XPS and time-of-flight SIMS analyses. These findings provide useful insights to engineer hybrid architectures that integrate bulk electro-optic crystals within superconducting cavities, proving that microwave quality factors compatible with high-efficiency microwave-optical transduction are within reach.
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BibTeX
@misc{reineri2026microwave,
title = {{Microwave dielectric properties of LiNbO$_\mathbf3$ and AlN at millikelvin temperatures and single-photon power}},
author = {Alessandro Reineri and Francesco Crisa and Maithlee Shinde and Daniel Bafia and Akshay Murthy and Changqing Wang and Tanay Roy and Alexander Romanenko and John Zasadzinski and Anna Grassellino and Silvia Zorzetti},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.22002},
eprint = {2609.22002},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22002},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Microwave dielectric properties of LiNbO_3 and AlN at millikelvin temperatures and single-photon power
AU - Alessandro Reineri
AU - Francesco Crisa
AU - Maithlee Shinde
AU - Daniel Bafia
AU - Akshay Murthy
AU - Changqing Wang
AU - Tanay Roy
AU - Alexander Romanenko
AU - John Zasadzinski
AU - Anna Grassellino
AU - Silvia Zorzetti
PY - 2026
DA - 2026/10/10
PB - arXiv
DO - 10.48550/arxiv.2609.22002
UR - https://arxiv.org/abs/2609.22002
AB - Efficient bidirectional microwave-optical photon conversion is a key capability for scaling superconducting quantum processors into distributed networks. However, achieving the necessary conversion efficiency requires filling a critical knowledge gap in understanding the loss mechanisms of electro-optic materials. Here, we characterize the microwave properties of single-crystal bulk LiNbO3 and AlN over a broad range of powers, down to single-photon levels, and spanning from millikelvin temperatures to above 1 K. We demonstrate that both materials exhibit two-level systems (TLS) behavior, while piezoelectric-related losses are excluded. We show that TLS-induced dissipation is predominantly localized on the surface rather than being an intrinsic bulk property, a result further corroborated by room-temperature 3D XPS and time-of-flight SIMS analyses. These findings provide useful insights to engineer hybrid architectures that integrate bulk electro-optic crystals within superconducting cavities, proving that microwave quality factors compatible with high-efficiency microwave-optical transduction are within reach.
ER -