Single multimode fibre for in vivo light-field-encoded endoscopic imaging

Abstract Super-resolution microscopy is typically not applicable to in situ imaging through a narrow channel due to the requirement for complex optics. Although multimode fibres (MMFs) have emerged as a potential platform for cost-effective and precise endoscopic imaging, they suffer from extreme sensitivity to bending and other external conditions. Here we demonstrate imaging through a single thin MMF for in vivo light-field encoded imaging with subcellular resolution. We refer to the technique as spatial-frequency tracking adaptive beacon light-field-encoded (STABLE) endoscopy. Spatial-frequency beacon tracking provides up to 1 kHz disorder tracking frequency, thus ensuring stable imaging through long-haul MMFs under fibre bending and various operating conditions. The full-vector modulation and fluorescence emission difference are combined to enhance the imaging signal-to-noise ratio and achieve a subdiffraction resolution of 250 nm. We integrate STABLE in a white-light endoscope and demonstrate cross-scale imaging in a bronchus model and in vivo imaging in mice models. The high-resolution and resilience to observation in a minimally invasive manner paves the way to the expansion of MMF in endoscopy to the study of disease mechanisms in biomedical sciences and clinical studies.