Non-contact optoacoustic imaging with focused air-coupled transducers

X. Luís Deán-Ben, Genny A. Pang, Francisco Montero de Espinosa, and Daniel Razansky
Applied Physics Letters, vol. 107, julio 2015, Issue 5

Non-contact optoacoustic imaging employing raster-scanning of a spherically focused air-coupled ultrasound transducer is showcased herein. Optoacoustic excitation with laser fluence within the maximal permissible human exposure limits in the visible and near-infrared spectra is applied to objects with characteristic dimensions smaller than 1 mm and absorption properties representative of the whole blood at near-infrared wavelengths, and these signals are shown to be detectable without contact to the sample using an air-coupled transducer with reasonable signal averaging. Optoacoustic images of vessel-mimicking tubes embedded in an agar phantom captured with this non-contact sensing technique are also showcased. These initial results indicate that an air-coupled ultrasound detection approach can be suitable for non-contact biomedical imaging with optoacoustics.

G.A.P acknowledges the support from the Technical University of Munich University Foundation Fellowship. F.M.E. acknowledges the support from CICYT DPI2013- 46915-C2-1-R Grant. D.R. acknowledges the support from the European Union under Grant Agreement No. ERC-2010-StG-260991.