Schematics of experimental systems used.

<p>(A) The VisualSonics Vevo LAZR uses intersecting planar laser beams (B) for excitation and a linear transducer array for 2D imaging of the resulting ultrasound. (C) The Endra Nexus 128 delivers diffuse laser light and detects the ultrasound using 128 transducers in a helical arrangement (D) for 3D reconstruction.