Partially-coherent illumination engineering for enhanced refractive index tomography

Optical diffraction tomography based on partially coherent illumination (PC-ODT) is a quantitative label-free imaging technique that allows reconstructing the object's 3D refractive index from measured through-focus intensity images. PC illumination provides advantages such as speckle noise-free imaging and inherent compatibility with conventional wide-field microscopes. Here, we experimentally demonstrate that a proper design of the PC illumination, different to the familiar bright-field one, and the use of more realistic optical transfer functions (OTFs) have a crucial importance in PC-ODT to significantly increase the accuracy in 3D RI reconstruction. While realistic OTFs properly account for the real experimental illumination conditions, the proposed PC illumination design allows for gathering the object spatial-frequency content attenuated when bright-field illumination is used.