Bragg Band Gap Engineering in Surface Acoustic Wave Devices for Tunable Phononic Topological Devices

The ability to engineer surface acoustic wave (SAW) devices with precise frequency control is crucial for the development of next-generation phononic systems. This work focuses on utilizing laser ablation techniques on Y-Cut 128° lithium niobate (LiNbO₃) substrates to create periodic surface structures aimed at introducing Bragg band gaps. These Bragg gaps are designed to enable selective frequency propagation, with the potential to serve as a platform for realizing topologically protected phononic waveguides. The control of surface geometry through laser ablation offers tunable frequency selectivity, a key feature for advancing robust RF applications. While topological acoustic (TA) properties remain a future target, this study marks an important step towards incorporating Bragg gap engineering into the design of phononic topological devices. The discussion will include the fabrication process, characterization, and future implications for integrating TA properties into RF devices to enhance their performance and robustness.