Reflection of parametric radiation from a finite planar target

Results are reported of an investigation of the reflection of parametric radiation from a finite planar target. The interference of the difference frequency sound generated after reflection with the reflected difference frequency sound is considered. Amplitude and phase were measured before and after reflection from a polyfoam target. Target size ranged from slightly larger than the beamwidth to smaller than the beamwidth. The results are compared with calculations based on equations describing the linear radiation and the parametric radiation. These equations are derived using the parabolic approximation.