High‐Efficiency Acousto‐Optic Modulation on Non‐Suspended Thin‐Film Lithium Tantalate

Acousto‐optic (AO) interactions provide a powerful interface between the microwave and optical domains, enabling optical switching, non‐reciprocal propagation, and efficient microwave‐to‐optical transduction. Here, we demonstrate high‐efficiency AO modulation on a non‐suspended lithium‐tantalate‐on‐insulator (LTOI) platform. LTOI combines intrinsically low birefringence, a high optical‐damage threshold, strong electro‐optic and Kerr nonlinearities, and favorable acoustic properties. Our Mach–Zehnder interferometers achieve , while racetrack resonators reach , enabling microwave‐to‐optical conversion without suspended structures. Measurements across six in‐plane propagation directions identify propagation along the crystal Z axis as the most efficient tested configuration, where the higher‐order R1 mode produces the strongest MZI response. Temperature‐dependent acoustic measurements and continuous RF‐driven optical testing further demonstrate material‐related operating stability. These results establish non‐suspended LTOI as a robust platform for integrated acousto‐optics with broad applications in communications, signal processing, and quantum information technologies.