Towards ultrathin fiber-optic probe for simultaneous photoacoustic and fluorescence endoscopy

A dual-modal photoacoustic and fluorescence endoscopy probe based on a single multimode fiber with a diameter of 140 µm was developed. By using a digital micromirror device with a high-speed algorithm for modulating the incident optical wavefront, the light transmission distortion through a multimode fiber was characterized and thus a focused laser beam was scanned at the distal fiber tip for microscopy imaging. Evaluation of the imaging performance was conducted with a dual-modal phantom comprising carbon fibers and fluorescence beads, and mouse red blood cells. The imaging probe has the potential to be further miniaturized using a fiber-optic ultrasound sensor so that it could be integrated into surgical tools such as medical needles for the guidance of minimally invasive procedures.