Lensless microendoscope for quantitative phase imaging with flexible working distance

Quantitative phase imaging (QPI) is essential in biomedicine and surface inspection for its 3D high-resolution imaging. Conventional QPI methods, hindered by large optical setups, face challenges in small spaces like in-vivo imaging of cancer tissues. To combat this, our study introduces a novel, ultra-thin, lensless microendoscope using multicore fiber, enabling effective QPI even in limited spaces. This device captures real-time holograms, reconstructing complex light fields with automatic digital refocusing, achieving up to 15 nm axial and 1-micron spatial resolution. Its compact 0.5 mm design significantly enhances access to restricted areas, revolutionizing surface inspection and in-vivo clinical diagnostic imaging.