Notice of Removal: Acoustical characterisation of carbon nanotube-loaded polydimethylsiloxane used for optical ultrasound generation

Optical ultrasound sources, which generate ultrasound photoacoustically, are promising alternatives to piezoelectric or capacitive transducers. Employing pulsed excitation light, high bandwidths (up to 100 MHz) and pressures (MPa range for unfocussed sources) have been achieved with materials that combine strong optical absorption with a high thermal expansion coefficient, such as carbon nanotube (CNT)-loaded polydimethylsiloxane (PDMS). However, literature suggests (Buma et al., IEEE tUFFC 50:9) that such composite materials often suffer from high acoustical attenuation, which limits the generated bandwidths and pressures. In this work, we present the broadband acoustical characterisation of both pure and CNT-loaded PDMS samples to assess the contributions of both constituents to the sound speed and attenuation coefficient.