Bimorph Lithium Niobate Thickness-Shear Overtone Film Bulk Acoustic Resonator
Abstract
High quality factor (Q) and overtone operation enable narrow-linewidth acoustic devices with multiple discrete frequencies in a single cavity. Maintaining both high Q and sufficient electromechanical coupling at higher mode orders remains challenging. Here, we demonstrate a bimorph periodically poled piezoelectric film (P3F) lithium niobate (LN) platform for high-order thickness-shear (TS) overtone excitation. The device comprises a bonded 80-μm-thick single-crystal X-cut LN bimorph with opposite polarizations, patterned top and floating bottom electrodes, and a suspended air cavity. The P3F configuration mitigates charge cancellation from the alternating stress distribution of higher-order TS modes, enabling measurable coupling across a broad sequence of overtones. The thick LN acoustic cavity and increasingly confined high-order mode profiles support low-loss operation. Measured TS overtones extend to 1.75 GHz. At room temperature, representative overtones at 0.77 and 0.89 GHz exhibit 3-dB Q values of 11,338 and 11,917, corresponding to fQ products of 8.74×1012 and 1.06×1013 Hz, respectively. Cooling from 297 to 12 K systematically enhances Q, yielding a peak 3-dB Q of 20,507 at 779 MHz and a maximum fQ product of 1.98×1013 Hz at 1.379 GHz. These results establish bimorph P3F LN as a promising platform for high-Q, frequency-scalable micro-acoustic resonators in the sub-GHz and low-GHz regimes.
Related
- Lithium Niobate Surface-Acoustic-Wave Resonator for Very-High-Frequency Isolated Power Conversion
- A material-agnostic platform to probe spin-phonon interactions using high-overtone bulk acoustic wave resonators
- Gigahertz-frequency Lamb-wave resonator cavities on suspended lithium niobate for quantum acoustics
- Demonstrating the thermal noise limit in a backaction-free bulk acoustic wave resonator chain for gravitational wave detection
- Icing monitoring with thickness shear acoustic waves
BibTeX
@misc{yao2026bimorph,
title = {{Bimorph Lithium Niobate Thickness-Shear Overtone Film Bulk Acoustic Resonator}},
author = {Ziqian Yao and Ian Anderson and Tzu-Hsuan Hsu and Vakhtang Chulukhadze and Jack Kramer and Ruochen Lu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14222},
eprint = {2609.14222},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14222},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Bimorph Lithium Niobate Thickness-Shear Overtone Film Bulk Acoustic Resonator
AU - Ziqian Yao
AU - Ian Anderson
AU - Tzu-Hsuan Hsu
AU - Vakhtang Chulukhadze
AU - Jack Kramer
AU - Ruochen Lu
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2609.14222
UR - https://arxiv.org/abs/2609.14222
AB - High quality factor (Q) and overtone operation enable narrow-linewidth acoustic devices with multiple discrete frequencies in a single cavity. Maintaining both high Q and sufficient electromechanical coupling at higher mode orders remains challenging. Here, we demonstrate a bimorph periodically poled piezoelectric film (P3F) lithium niobate (LN) platform for high-order thickness-shear (TS) overtone excitation. The device comprises a bonded 80-μm-thick single-crystal X-cut LN bimorph with opposite polarizations, patterned top and floating bottom electrodes, and a suspended air cavity. The P3F configuration mitigates charge cancellation from the alternating stress distribution of higher-order TS modes, enabling measurable coupling across a broad sequence of overtones. The thick LN acoustic cavity and increasingly confined high-order mode profiles support low-loss operation. Measured TS overtones extend to 1.75 GHz. At room temperature, representative overtones at 0.77 and 0.89 GHz exhibit 3-dB Q values of 11,338 and 11,917, corresponding to fQ products of 8.74×10^12 and 1.06×10^13 Hz, respectively. Cooling from 297 to 12 K systematically enhances Q, yielding a peak 3-dB Q of 20,507 at 779 MHz and a maximum fQ product of 1.98×10^13 Hz at 1.379 GHz. These results establish bimorph P3F LN as a promising platform for high-Q, frequency-scalable micro-acoustic resonators in the sub-GHz and low-GHz regimes.
ER -