3D-printed endo-microscope with a fast magnetic actuator for axial image plane scanning

Miniaturized endo-microscopes enable imaging with cellular resolution in hard-to-access, confined spaces. Femtosecond 3D-printing provides ultra-compact imaging optics (∅<1 mm) with a suitably fine lateral imaging resolution. The large numerical aperture of endo-microscopes, however, entails a small depth of field that prohibits sharp imaging of volumetric structures. Combining 3D-printed micro-optics with a recently presented magnetic actuator at the tip of an imaging fiber bundle allows fast axial image plane scanning (up to 20 Hz) in a compact (∅= 650 µm) endo-microscope with high lateral resolution (∆x ≈ 7 µm). The magnetic actuator allows the acquisition of sharp images of 3D structures despite the short depth of field, overcoming this limitation of state-of-the-art static endo-microscopes.