Two-dimensional ultrasound detection with an optical multilayer hydrophone using serial and parallel data acquisition

An optical technique is presented that allows the two-dimensional determination of ultrasound pressure using an optical multilayer hydrophone where a laser beam detects the change in reflectivity of a dielectric coating system due to incident ultrasound. Two-dimensional data acquisition covering an area of at least 15×5 mm² was realized by a serial technique using a micromechanically-engineered scanning mirror and a parallel technique exploiting a CCD camera. Measurement results on ultrasound fields from plane and focusing transducers are presented and compared.