Optical multilayer detection array for fast ultrasonic field mapping

An optical multilayer detection array for ultrasonic measurements is presen ted. The probe comprises a dielectric interference filter structure that is evaporated onto a glass plate. An incident acoustic pressure signal deform s the layer system, and the induced modulation of the optical reflectance i s determined by a simple optical detection scheme. The principle of measure ment is demonstrated by a line scan through the focus of a broadband transd ucer and can be applied to rapid two-dimensional characterization of ultras onic fields. The high temporal and spatial resolution of the measurements i s combined with high sensitivity and durability of the probe, and, in contr ast with fiber-tip multilayer hydrophones, the multilayer detection array p rovides signals that are not influenced by acoustic resonances and diffract ion phenomena. (C) 1999 Optical Society of America.