Local Observation of the 2nd-Order Harmonics Generated in RF-SAW Devices

The local observation of the complex amplitude corresponding to the harmonic response generated in the RF-SAW device was carried out by probing within a narrow scanning area. This local observation provides high spatial resolution and highly sensitive detection of acoustic vibrations on the device surface within a reasonable measurement time. The local observation showed that anomalous excitation of the H2 response occurs on the device. Furthermore, surface displacements corresponding to the H2 and the linear responses are 2D mapped in a narrow area using the Michelson interferometer. The measurement results suggest that the displacement of the H2 is on the order of picometers and about 10 to 100 times smaller than that of the linear response. Based on these demonstrations, the local observation of the harmonics is a powerful tool for revealing the nonlinear behavior occurring in the RF SAW device.