摘要：

Quantitative Phase Imaging (QPI) and Optical Diffraction Tomography (ODT) are powerful label-free techniques, but conventional off-axis systems suffer from environmental instability and speckle noise due to highly coherent illumination requirements. In this seminar, I will present a novel, highly robust common-path diffraction grating based framework that overcomes these limitations, enabling high-fidelity 3D refractive index imaging. By deploying compact, open-top architectures with advanced polarization gratings, the system enables the use of low-coherence light sources, thereby drastically reducing parasitic interference and speckle noise. To address the main limitation of common-path systems, which is the object replica problem, we introduce a suite of computational methods.

For total-shear systems, the R2D-QPI method analytically eliminates the replica conjugate image, effectively doubling the usable field of view for highly confluent samples. In small-shear configurations, to retrieve phase from its derivative, the open-source OSI-flex framework guarantees robust joint phase and shear retrieval via adaptive optimization.

For 3D tomography, we introduced the Gradient Optical Diffraction Tomography (GODT) concept, which directly reconstructs the 3D refractive index directional derivative from phase gradient measurements. Demonstrated across 3D-printed phantoms, neurons, and label-free lipidomic assays, this our common path platform provides robust, high-throughput holotomography, setting a new standard for biomedical imaging.

报告人简介：

Piotr Zdańkowski is an assistant professor at the Institute of Micromechanics and Photonics, Faculty of Mechatronics, Warsaw University of Technology. He specializes in advanced optical imaging techniques, with a primary focus on super-resolution microscopy, adaptive optics, quantitative phase imaging (QPI), and optical diffraction tomography (ODT). Piotr earned his PhD from the University of Dundee in 2018, where he was developing a system integrating adaptive optics into stimulated emission depletion (STED) microscopy, for 3D imaging of biological samples.

Currently, Piotr co-leads the Quantitative Computational Imaging Lab (QCI Lab), developing cutting-edge imaging methodologies including common-path QPI and ODT, Fourier Ptychographic Microscopy (FPM), lensless microscopy and super-resolution fluorescence microscopy.