Single-shot depth profiling by spatio-temporal encoding with a multimode fiber.

Computational imaging with random encoding patterns obtained by scattering of light in complex media has enabled simple imaging systems with compelling performance. Here, we extend this concept to axial reflectivity profiling using spatio-temporal coupling of broadband light in a multimode fiber (MMF) to generate the encoding functions. Interference of light transmitted through the MMF with a sample beam results in path-length-specific patterns that enable computational reconstruction of the axial sample reflectivity profile from a single camera snapshot. Leveraging the versatile nature of MMFs, we demonstrate depth profiling with bandwidth-limited axial resolution of 13.4 µm over a scalable sensing range reaching well beyond one centimeter.