Broadband all-optical ultrasound transducers

A broadband all-optical ultrasound transducer has been designed, fabricated, and tested for high-resolution ultrasound imaging. It consists of a two-dimensional gold nanostructure on a glass substrate, followed by a 3 mu m polydimethylsiloxane layer and a 30 nm gold layer. The signal to noise ratio of a pulse-echo signal is over 10 dB in the far field of the transducer, where the center frequency is 40 MHz with -6 dB bandwidth of 57 MHz. The potential for high-frequency ultrasound arrays using this technology is demonstrated using multiple measurements from the transducer to image a 25 mu m diameter wire. (C) 2007 American Institute of Physics.