A novel laser ultrasound transducer using candle soot carbon nanoparticles

Laser ultrasound provides a useful method to generate high frequency, broadband and high intensity acoustic waves. In this study, we demonstrated a novel optoacoustic transducer with high-energy conversion efficiency by using candle soot nanoparticles polydimethylsiloxane (CSPs-PDMS) composite. Carbon nanoparticles are used because of their excellent properties of light absorption and heat transfer. The mean diameter of collected candle soot carbon nanoparticles is about 40 nm, and the light absorption ratio at 532 nm wavelength is up to 96.24%. The prototyped CSPs-PDMS composite laser ultrasound transducer was excited by laser pulses, and the acoustic beam profile was measured and compared with Field II simulation results. Energy conversion coefficient and -6 dB frequency bandwidth of CSPs-PDMS composite laser ultrasound transducer were measured to be 4.41 × 10^-3 and 21 MHz, respectively. The unprecedented laser ultrasound transduction performance using CSNPs-PDMS nano-composites is promising for a broad range of ultrasound therapy and non-destructively testing applications.