Time-of-flight 3D imaging through multimode optical fibers

TLDR

Time‑of‑flight 3D imaging, which recovers depth by measuring laser pulse round‑trip times, is used in industrial inspection and motion tracking but traditionally requires centimeter‑scale collection optics. The study demonstrates near‑video‑rate 3D imaging through multimode fibers with a total aperture of several hundred micrometers. The authors use wavefront‑shaped aberration correction synchronized with a pulsed source to scan scenes at ~23,000 points per second, enabling imaging of moving objects several meters beyond a 40‑cm multimode fiber. The technique allows imaging of moving objects several meters beyond a 40‑cm, 50‑µm core multimode fiber at ~5 Hz, providing far‑field depth‑resolving capability for ultrathin microendoscopes in clinical and remote inspection.

Abstract

Time-of-flight three-dimensional (3D) imaging has applications that range from industrial inspection to motion tracking. Depth is recovered by measuring the round-trip flight time of laser pulses, typically using collection optics of several centimeters in diameter. We demonstrate near–video-rate 3D imaging through multimode fibers with a total aperture of several hundred micrometers. We implement aberration correction using wavefront shaping synchronized with a pulsed source and scan the scene at ~23,000 points per second. We image moving objects several meters beyond the end of an ~40-centimeters-long fiber of 50-micrometer core diameter at frame rates of ~5 hertz. Our work grants far-field depth-resolving capabilities to ultrathin microendoscopes, which we expect to have applications to clinical and remote inspection scenarios.