Development of arrays of highly sensitive plano-concave optical microresonator sensors for photo-acoustic imaging applications (Conference Presentation)

Photoacoustic imaging technology is a non-invasive imaging platform for visualizing the structure and function of soft tissues. In this paper, an array of highly sensitive Fabry-Perot (FP) planoconcave micro-resonator (PCMR) sensors are being developed which can allow the imaging depth beyond a few centimeters which was never possible for a typical planar FP sensor. The optical confinement factor of the sensor was found to be (>10^5) and noise equivalent pressure is around ~ 20 mPa per 20 MHz measurement bandwidth. In this work, a new approach to reading-out an array of PCMR sensors which efficiently identifies the optimum spatial locations of each PCMR and mitigates the sensitivity reduction due to self-heating has been demonstrated. This novel system has the potential to deliver improved image SNR compared to previously reported planar FP sensors for the clinical assessment of deeply lying pathologies such as breast tumours and malignant lymph nodes.