High resolution acoustic field imaging applied to surface acoustic wave devices

This paper reports measurements of acoustic wave amplitude distributions within SAW devices with high spatial resolution. A modified scanning force microscope transfers the high frequency surface oscillations of the SAW into detectable cantilever vibrations by exploiting a nonlinear coupling mechanism. The capabilities of our technique are demonstrated on conventional Rayleigh wave devices up to 3 GHz and on surface transverse wave resonator devices, where the amplitude in the reflector section was mapped. The demonstrated spatial resolution of the imaged SAW amplitude patterns considerably exceeds the results obtained by conventional techniques.