Diagnostics and doppler tomography of liquid flows with ultrasonic phase conjugation

The potential of ultrasonic velocimetry and mapping for liquid flows in a model and real biological media is demonstrated experimentally and theoretically using the technique of parametric phase conjugation of sound. The basis of the proposed method is violation of invariance of an acoustic field with respect to time reversal in a moving medium that leads to an uncompensated phase shift of a phase-conjugate wave at a transmitter-receiver array. The principles for application of nonlinear acoustic effects for improving the reconstruction precision for the field of flow velocities are discussed.