Resolution enhancement of quantitative phase microscopy with vortex beam illumination

Quantitative phase microscopy (QPM) is crucial for label-free imaging of biological specimens and materials. Due to the diffraction limit, the lateral resolution of QPM cannot satisfy the growing demand to resolve subcellular structures around 100 nm in living cells. Vortex beams offer promising capabilities in optical imaging by enabling tight focusing and non-diffracting propagation. We propose the use of vortex beam for illumination in an off-axis QPM system and developed the imaging theory from vector diffraction. Our preliminary results show the spatial resolution and the image contrast can be improved on both biological and material samples.