Time-resolved quantitative multiphase interferometric imaging of a highly focused ultrasound pulse

Interferometric imaging is a well-established method to image phase objects by mixing the image wavefront with a reference one on a CCD camera. It has also been applied to fast transient phenomena, mostly through the analysis of single interferograms. It is shown that, for repetitive phenomena, multiphase acquisition brings significant advantages. A 1 MHz focused sound field emitted by a hemispherical piezo-transducer in water is imaged as an example. Quantitative image analysis provides high resolution sound field profiles. Pressure at focus determined by this method agrees with measurements from a fiber-optic probe hydrophone. This confirms that multiphase interferometric imaging can indeed provide quantitative measurements. (C) 2010 Optical Society of America