Using a multimode optical fiber as thin as a human hair, scientists at the Leibniz-Institute of Photonic Technology have observed at high resolution the neuronal structures inside deep brain areas of living mice. The researchers drew on holographic methods for controlling light to design a fluorescence imaging system compact enough to fit on the tip of a fiber. The ultranarrow, minimally invasive probe offers a smaller footprint and higher resolution compared to endoscopes based on graded-index lenses or fiber bundles.
According to the researchers, the new probe is capable of acquiring 7-kilopixel images with micron-level spatial resolution at imaging speeds of 3.5 frames/s. These results could provide adequate spatial and temporal resolution for fluorescent imaging of subcellular structures in living tissues.