Mode conversion in high overtone bulk acoustic wave resonators

High overtone bulk acoustic resonators (HBAR) have been realized using the Smart Cuttrade technology to transfer a thin X-cut LiNbO
₃
layer onto an X-cut LiNbO
₃
substrate. When the bonding of the two wafers is performed, an additional rotation along the normal axis is set to generate mode conversion between the two acoustic shear waves electromechanically coupled in X-cut LiNbO
₃
. This enables excitation of only one of the two acoustic shear waves.