Broadband piston mode operation of solidly mounted resonator employing A1 Lamb mode on lithium niobate

Abstract

This paper discusses the impact of etched holes given to the solidly mounted resonator (SMR)-supported A1 Lamb mode resonators. The authors pointed out that the etched holes are effective at suppressing the lateral leakage and the transverse mode resonances for free-standing A1 Lamb mode resonators, and the technique was named the broadband piston mode (BPM). First, the SMR structure is designed for an A1 Lamb mode resonator, and it is shown that the release windows are effective in the suppression of transverse mode resonances even when the SMR is added. Detailed analysis is given to spurious responses that newly appeared by applying the SMR. Then, the discussion is extended to the impact of partial etching of the SMR layers underneath the release windows. The result indicates that the etching of the top SMR layer is enough for recovery of the BPM function.