Experimentally constrained modeling of the Pockels response of KNbO3 and KTaNbO3
Abstract
The soft-mode of electro-optic (EO) metal-oxide perovskites plays a critical role in determining their Pockels responses. This is the case of potassium tantalate niobate (KTN), which exhibits an intrinsic Pockels response 2.5 times larger than that of state-of-the-art barium titanate (BTO), highlighting its potential for high-performance EO applications. By combining ab initio calculations at the density-functional theory level and far-IR measurements, we reveal that the harmonic approximation combined with semi-local exchange-correlation functionals fails to accurately capture the soft transverse optical (TO) Slater mode of both potassium niobate and KTN, which dominates the technologically relevant r51 Pockels coefficient. Replacing the calculated mode frequency with its measured value provides an experimentally constrained approach that substantially improves the predicted Pockels response. For that purpose, the previously unreported TO Slater-mode frequency of KTN is extracted from far-IR reflectivity measurements. The results emphasize the potential of KTN-based EO modulators as an alternative to standard lithium niobate and BTO technologies, with a potentially lower energy consumption and device footprint.
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BibTeX
@misc{mestral2026experimentally,
title = {{Experimentally constrained modeling of the Pockels response of KNbO3 and KTaNbO3}},
author = {Virginie de Mestral and Lorenzo Bastonero and Petr Bednyakov and Fedir Borodavka and Simon Mellaerts and Tetyana Ostapchuk and Alex Pescaru and Jiri Hlinka and Mathieu Luisier},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.03888},
eprint = {2609.03888},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.03888},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Experimentally constrained modeling of the Pockels response of KNbO3 and KTaNbO3
AU - Virginie de Mestral
AU - Lorenzo Bastonero
AU - Petr Bednyakov
AU - Fedir Borodavka
AU - Simon Mellaerts
AU - Tetyana Ostapchuk
AU - Alex Pescaru
AU - Jiri Hlinka
AU - Mathieu Luisier
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.03888
UR - https://arxiv.org/abs/2609.03888
AB - The soft-mode of electro-optic (EO) metal-oxide perovskites plays a critical role in determining their Pockels responses. This is the case of potassium tantalate niobate (KTN), which exhibits an intrinsic Pockels response 2.5 times larger than that of state-of-the-art barium titanate (BTO), highlighting its potential for high-performance EO applications. By combining ab initio calculations at the density-functional theory level and far-IR measurements, we reveal that the harmonic approximation combined with semi-local exchange-correlation functionals fails to accurately capture the soft transverse optical (TO) Slater mode of both potassium niobate and KTN, which dominates the technologically relevant r51 Pockels coefficient. Replacing the calculated mode frequency with its measured value provides an experimentally constrained approach that substantially improves the predicted Pockels response. For that purpose, the previously unreported TO Slater-mode frequency of KTN is extracted from far-IR reflectivity measurements. The results emphasize the potential of KTN-based EO modulators as an alternative to standard lithium niobate and BTO technologies, with a potentially lower energy consumption and device footprint.
ER -