Domain-engineered, aperiodically-poled KTiOPO4 for polarization-entangled photons

Published

April 20, 2026

Author(s)

Paulina Kuo, Sesha Challa, Anouar Rahmouni, Dileep Venkatarama Reddy, Ori Levin, Noa Bloch

Abstract

We demonstrate a high-quality source of polarization-entangled photons in aperiodically-poled KTiOPO_4 (KTP). The crystal is based on a phase-modulated domain-engineered design that allows two simultaneous downconversion processes, where the two processes correspond to the two terms of the entangled-photon state. We characterized the temperature tuning of both the spectral response and the polarization-fringe visibility for spontaneous parametric downconversion (SPDC) using this crystal. At the optimum temperature where wavelength distinguishability of the two SPDC processes is smallest, we obtained average polarization-entanglement visibility 0.984 ± 0.003 with a measured Clauser–Horne–Shimony–Holt (CHSH) parameter S = 2.801 ± 0.014. We also discuss the effects of the relative phase in the entangled-photon state and present a new way to compensate for these effects to obtain high polarization-entanglement visibility.

Citation

Optical Materials Express

Pub Type

Journals

Download Paper

https://doi.org/10.1364/OME.587330

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Keywords

spontaneous parametric downconversion, quantum networking

Citation

Kuo, P. , Challa, S. , Rahmouni, A. , Venkatarama Reddy, D. , Levin, O. and Bloch, N. (2026), Domain-engineered, aperiodically-poled KTiOPO4 for polarization-entangled photons, Optical Materials Express, [online], https://doi.org/10.1364/OME.587330, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=961273 (Accessed April 25, 2026)

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