Nonlinear energy exchange among harmonic modes and its applications to nonlinear imaging

Nonlinear energy exchange and redistribution among the harmonic modes have been investigated. A problem with the pre-bias boundary condition, which means that in addition to the fundamental harmonic, nonzero higher harmonics with adjustable amplitudes and phases are also applied to the input simultaneously, has been considered. The results show that the pre-bias technique that is proposed in this paper may offer a better means for detecting the nonlinear properties of the medium. The feasibility of the approach was validated by computer simulation and experimental results.