Fiber optic photoacoustic ultrasound generator based on gold nanocomposite

Recently, many advanced ultrasound applications require wide bandwidth and compact ultrasound generators to achieve better resolution as well as the capability of being operated in a compact space. Generating ultrasound signals through photoacoustic principle is a promising way to generate wide bandwidth ultrasound signals by the optical approach. Meanwhile, optical fibers are ideal candidates for applications where compact size is required. Therefore, fiber optic photoacoustic generators, which put advantages of the photoacoustic principle and optical fibers together, lead to novel ultrasound generation devices which can meet the most advanced ultrasound applications requirements. This paper firstly reports using the gold nanocomposite to achieve the fiber optic photoacoustic ultrasound generator. The gold nanocomposite was synthesized by directly mixing the gold salt in polydimethylsiloxane. The gold nanocomposite showed high optical energy absorption capability and the high coefficient of thermal expansion. The photoacoustic generation efficiency was increased by applying such material. The synthesis protocol of the gold nanocomposite was presented in this paper. The optical fiber was coated with the gold nanocomposite to generate ultrasound signals. Experimental results have demonstrated that ultrasound signals can be generated by this approach and the fiber optic ultrasound generator can be used in ultrasound applications.