Plano-concave microresonator sensors for photoacoustic imaging: optical sensitivity maximization using transfer matrix model

Deep tissue applications (>1 cm) for photoacoustic imaging are currently limited for traditional Fabry-Perot ultrasound transducers interrogated by tightly focused Gaussian beams due to beam walk-off. We investigate the optical confinement of the beam using plano-concave microresonators with a model based on the ABCD formalism and the use of high-sensitive and high-density multi-element arrays. The results show an improvement in the sensitivity enabling an increase of the penetration depth in tomographic photoacoustic imaging.