Optical-resolution photoacoustic microscopy system with boxer engine-inspired mechanical scanning.

A boxer engine is a type of engine that was developed to more effectively cancel out the mechanical vibration that occurs when the engine operates by arranging a pair of slider-crank structures in a symmetrical form. In this study, inspired by that mechanical concept, we designed and implemented a new scanner device that can improve the scanning speed of conventional linear reciprocating scanners by about tenfold without compromising the scanning range. Moreover, by applying the femtosecond laser processing technology, we implemented a customized optical encoder module as well as a large aperture (9 mm dia.) focused ultrasonic ring transducer, which enabled the successful embodiment of an optical-resolution photoacoustic microscopy system along with the new scanner concept. As the linear reciprocating scanning mechanism has been applied as a central element in various mechanical systems, we expect that the presented concept could be a useful option not only in the biophotonic field but also in many areas of industry.