Ultrasonic imaging of the nonlinear parameter B/A: Simulation studies to evaluate phase and frequency modulation methods

This paper presents a method for imaging the nonlinear parameter B/A. It is based on measuring phase shift and frequency shift of a high frequency acoustic probe wave by a low frequency acoustic pump wave. These measurements yield the real and the imaginary parts of the Fourier component of the distribution B/A at the wave number of the pump wave. We also derive the necessary set of wave numbers of the pump wave which must be employed to accurately image the B/A parameter. We show that these wave numbers are a function of sampling period and sampling number. Simulations of the imaging method show that the proposed method in this paper leads to more accurate imaging of B/A than the earlier method.