Label-free quantitative 3D intensity diffraction tomographic imaging in high numerical aperture microscopy

We propose label-free and motion-free resolution-enhanced intensity diffraction tomography recovering the 3D complex refractive index distribution of an object. By combining an annular illumination strategy with a high numerical aperture (NA) condenser, we achieve near diffraction-limited lateral resolution of 346 nm and axial resolution of 1.2 µm over 130 130 8 µm3 volume. Our annular pattern matches the system’s maximum NA to reduce the data requirement to 48 intensity frames. The small data requirement and high resolution enable fast 3D quantitative refractive index imaging of biological cells across hundreds of nanometers scales. The reIDT system is directly built on a standard commercial microscope with a simple LED array source and condenser lens adds-on, and promises broad applications for natural biological imaging with minimal hardware modifications. To test the capabilities of our technique, we present the 3D complex refractive index reconstructions on the Henrietta Lacks (HeLa) and HT29 human cancer cells. Our work provides an important step in intensity-based diffraction tomography towards high resolution imaging applications.