Optical diffraction tomography (ODT) is a three-dimensional (3D) quantitative phase imaging technique, which enables the reconstruction of the 3D refractive index (RI) distribution of a transparent sample. Due to its fast, noninvasive, and quantitative 3D imaging capability, ODT has emerged as one of the most powerful tools for various applications. However, the spatial resolution of ODT has only been quantified along the lateral and axial directions for limited conditions; it has not been investigated for arbitrary-oblique directions. In this paper, we systematically quantify the 3D spatial resolution of ODT by exploiting the spatial bandwidth of the reconstructed scattering potential. The 3D spatial resolution is calculated for various types of ODT systems, including the illumination-scanning, samplerotation, and hybrid scanning-rotation methods. In particular, using the calculated 3D spatial resolution, we provide the spatial resolution as well as the arbitrary sliced angle. Furthermore, to validate the present method, the point spread function of an ODT system is experimentally obtained using the deconvolution of a 3D RI distribution of a microsphere and is compared with the calculated resolution. The present method for defining spatial resolution in ODT is directly applicable for various 3D microscopic techniques, providing a solid criterion for the accessible finest 3D structures.

ABSTRACT:In this study the PPS/ABS blend system was investigated in order to collectively identify the relationship among blend morphology, chemical compatibilization, and thermal property. The ABS resin was chemically modified by the incorporation of maleic anhydride through reactive extrusion for enhanced compatibilization, and ABS/PPS and the modified ABS/PPS blends were prepared by a twinscrew extruder. The effect of chemical modification of ABS on the morphological, mechanical, and thermal properties of the resulting blend was examined. A strong chemical interaction between PPS and MABS was observed by optical microscopy, scanning electron microscopy, and FTIR. The PPS/MABS blend showed a single glass-transition temperature in dynamic mechanical analysis, demonstrating pseudo-homogeneous phase morphology induced by chemical compatibilization. The PPS/MABS blend also exhibited an enhanced thermal stability and heat distortion temperature compared with the PPS/ABS blend.

Optical diffraction tomography (ODT) is a three-dimensional (3D) label-free imaging technique. The 3D refractive index distribution of a sample can be reconstructed from multiple two-dimensional optical field images via ODT. Herein, we introduce a temporally low-coherence ODT technique using a ferroelectric liquid crystal spatial light modulator (FLC SLM). The fast binary-phase modulation provided by the FLC SLM ensures a high spatiotemporal resolution with considerably reduced coherent noise. We demonstrate the performance of the proposed system using various samples, including colloidal microspheres and live epithelial cells.

Three-dimensional (3D) refractive index (RI) imaging and quantitative analyses of angiosperm pollen grains are presented. Using optical diffraction tomography, the 3D RI structures of individual angiosperm pollen grains were measured without using labeling or other preparation techniques. Various physical quantities, including volume, surface area, exine volume, and sphericity, were determined from the measured RI tomograms of pollen grains. Exine skeletons, the distinct internal structures of angiosperm pollen grains, were identified and systematically analyzed.