Photoacoustic endomicroscopy based on a MEMS scanning mirror

In this Letter, we present a high-resolution photoacoustic endomicroscopy probe based on a microelectromechanical systems (MEMS) scanning mirror. The built-in optical assembly consists of a 0.7 mm graded-index (GRIN) lens for light focusing and a ϕ1  mm MEMS mirror to reflect and scan the beam. A miniaturized unfocused ultrasound transducer with a center frequency of 10 MHz is used for photoacoustic detection. Sharp blades, carbon fibers, and black tapes were utilized to evaluate the performance of the system. In vivo mouse ears and resected rectums were imaged to further demonstrate the feasibility of this probe for potential biological and clinical applications.