Phase accurate optical probing of surface acoustic wave devices

In this letter, we present a method which detects the angle deflection of a laser beam due to the mechanical undulation of the substrate surface. This method allows us to measure amplitude and phase of a surface acoustic wave with high spatial resolution. Because of the use of a picosecond laser source the method has a bandwidth of 10 GHz limited only by the jitter of the driving electronics and the spot size of the laser beam. In addition we report first measurements at frequencies up to 1 GHz.