Fiber-optic large-depth 3D chromatic confocal endomicroscopy

Abstract

Current endoscopy techniques have difficulties to provide both high resolution and large imaging depth, which significantly hinders the early diagnosis of gastric cancer. Here, we developed a label-free, large-depth, three-dimensional (3D) chromatic reflectance confocal endomicroscopy. In order to solve the problem of insufficient imaging depth of traditional chromatic confocal microscopy, a customized miniature objective lens both with large chromatic focal shift and correction for spherical aberration was used to focus light of different wavelengths at different depths of the sample simultaneously, and a fiber bundle containing 50000 single-mode cores was used to collect the confocal reflectance signal. To acquire detailed information along the axial direction at a faster speed, a high-speed multi-pixel spectrometer was used to realize simultaneous detection of multi-depth signals. Specifically, we have built up a label-free fiber-optic 3D chromatic reflectance confocal endomicroscopy, with 2.3 µm lateral resolution, imaging depth of 570 µm in 3D phantom and 220 µm in tissue, and 1.5 Hz 3D volumetric frame rate. We have demonstrated that the fiber-optic 3D chromatic confocal endomicroscopy can be used to image human gastric tissues ex vivo, and provide important morphological information for diagnosis without labeling. These results show the great potential of the fiber-optic 3D chromatic confocal endomicroscopy for gastric cancer diagnosis.

Time‐stretch Chromatic Confocal Microscopy for Multi‐Depth Imaging

“…In our previous work, we customized a dispersive microlens with large axial chromatic focal shift and small spherical aberration, and the averaged axial resolution was ≈12 µm. [ 9 ] The customized microlens had a NA of 0.3 and its working wavelength ranged from 650 to 950 nm (specification is in Table S1, Supporting Information and design information is in Table S2, Supporting Information). For spatial dispersion in the TSCCM, we used the customized microlens to focus broadband spectrum at different depths.…”