Fiber-Tip Photoacoustic Probe With Mos2-Pdms Composite Coating For Temperature And Density-Induced Ultrasonic Speed Tuning

We demonstrate here a miniature broadband (up to similar to 12.8 MHz) fiber-tip photoacoustic probe with similar to 68.32-mu m thick MoS2-polydimethylsiloxane (PDMS) composite coating for ultrasound velocity adjustment by the regressive dependence on the temperature and density of saline solution. The composite was applied to the tip of a double-clad fiber with an outer diameter of 125 mu m using drop casting. Under a 5-ns pulsed laser excitation, the developed probe sensitivities to temperature and density in the range of 20-50 degrees C and 0.991-10 g/cm(3) were investigated in terms of the change in velocity and attenuation of ultrasonic wave transmitting in the saline solution. An excellent goodness of fit (R-2>0.99) and significance of the binary linear regression (F>>F-0(.01)) were achieved with the corresponding mean relative errors of 0.38% and 0.12% for measured temperatures and densities, along with a tunable range of 1478.51 to 1679.13 m/s. The proposed technique could therefore be extended for in situ matching ultrasound velocity of coupling liquid at the transducer-tissue boundary' in optoacoustic imaging. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement