Fig. 1: Suspended Lamb-wave resonators (LWRs) with varying thicknesses.

a Image of the prepared lithium niobate-on-insulator (LNOI) chip featuring areas with multiple thickness levels: 67, 107, 165, 230, and 300 nm. The variation in colors in the central region is due to the light reflection of a fluorescent lamp, highlighting the differing thickness levels across the chip. Inset shows the incremental thickness steps of lithium niobate (LN) film. b Image of the chip with fabricated devices. Five regions labeled (i) to (v) are marked. c Cross-sectional schematics of the suspended LWRs with varying LN thicknesses: 67 nm (i), 107 nm (ii), 165 nm (iii), 230 nm (iv), 300 nm (v).