Super-resolution measurement of thermo-optic coefficient of KTP crystal based on phase amplification

Fuente: arXiv
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Main Authors: Li, Wuzhen, Zhou, Zhiyuan, Guo, Guangcan, Shi, Baosen
Format: Preprint
Published: 2025
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_version_ 1866915194106544128
author Li, Wuzhen
Zhou, Zhiyuan
Guo, Guangcan
Shi, Baosen
author_facet Li, Wuzhen
Zhou, Zhiyuan
Guo, Guangcan
Shi, Baosen
contents Given that the phase amplification method based on harmonic generation exhibits significant phase super-resolution capability in interferometric precision measurement, extending this technology to birefringence interferometers to achieve super-resolution characterization of birefringent crystal properties has important research significance and application value. Here, we achieve a four-fold enhancement in the measurement resolution of the thermo-optic coefficient of a KTiOPO4 crystal by combining a self-stabilized birefringence interferometer with cascaded second harmonic generation processes. We observe the tunable interference beating phenomenon by rotating a birefringent crystal versus the temperature of the crystal for the fundamental wave, second harmonic, and fourth harmonic. Furthermore, the fourth harmonic interference fringes beat 4 times faster than the fundamental wave interference fringes. This beating effect is used to determine the thermo-optic coefficients of the two principal refractive axes with a single measurement. This work provides a feasible, real-time, and robust method for super-resolution measurements based on birefringence interferometry.
format Preprint
id arxiv_https___arxiv_org_abs_2503_09023
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Super-resolution measurement of thermo-optic coefficient of KTP crystal based on phase amplification
Li, Wuzhen
Zhou, Zhiyuan
Guo, Guangcan
Shi, Baosen
Optics
Given that the phase amplification method based on harmonic generation exhibits significant phase super-resolution capability in interferometric precision measurement, extending this technology to birefringence interferometers to achieve super-resolution characterization of birefringent crystal properties has important research significance and application value. Here, we achieve a four-fold enhancement in the measurement resolution of the thermo-optic coefficient of a KTiOPO4 crystal by combining a self-stabilized birefringence interferometer with cascaded second harmonic generation processes. We observe the tunable interference beating phenomenon by rotating a birefringent crystal versus the temperature of the crystal for the fundamental wave, second harmonic, and fourth harmonic. Furthermore, the fourth harmonic interference fringes beat 4 times faster than the fundamental wave interference fringes. This beating effect is used to determine the thermo-optic coefficients of the two principal refractive axes with a single measurement. This work provides a feasible, real-time, and robust method for super-resolution measurements based on birefringence interferometry.
title Super-resolution measurement of thermo-optic coefficient of KTP crystal based on phase amplification
topic Optics
url https://arxiv.org/abs/2503.09023