Generation and Applications of Broadband High-frequency Laser Ultrasound with Nanostructured Materials

In the present work we show that the interaction between short lasers pulses and tailor-made nanostrucured materials can produce broadband high-frequency ultrasound. In order to obtain efficient light-to-pressure conversion we used nanostructured carbon nanotubes permeated with high thermal expansion polydimethylsiloxane and nanometric TiO2 particles with adsorbed dye infused polystyrene. It is possible to achieve ultrasound pulses with central frequencies of 80 MHz and bandwidths of 125 MHz (at -6 dB) using a 6 ns pulsed laser. The aforementioned materials are used in order to establish proof-of-concept of the non-destructive ultrasound pulses interaction with biological membranes, exemplified by the unloading of Green Fluorescence Protein from giant unilamellar vesicles, and of non-invasive material inspection, illustrated with the measurement of the thickness of thin paint layers based on ultrasound frequency attenuation.

Automated summary

In this study, it was demonstrated that the interaction between short laser pulses and tailor-made nanostructured materials can generate broadband high-frequency ultrasound. The potential applications of this technology include non-destructive ultrasound interaction with biological membranes and non-invasive material inspection.