Dr. Dipin SINHA of Los Alamos National Laboratory

Swept Frequency Acoustic Interferometry (SFAI) was developed specifically to identify highly toxic chemicals inside sealed munitions almost two decades ago. SFAI is based on setting up standing waves (resonance) inside a fluid-filled (liquid, mixture, suspension, emulsions, gas etc.,) container. These resonances are typically observed over a wide range of ultrasonic frequency in the form of a spectrum that contains information on a large number of physical properties (sound speed, sound absorption, density, viscosity, and acoustic nonlinearity). So, a single spectrum can provide multiple measurements at the same time.  There are several ways SFAI can be implemented in practice and there are many applications of this technique in different fields. SFAI at low power can be used as a probing technique to characterize fluids in a noninvasive manner.  However, at higher power, SFAI can be used for ultrasonic manipulation of particles in a host medium and create artificially engineered materials. I will describe the SFAI technique and how it can be used in practice for