Polarization wavefront shaping for quantitative phase contrast and NLO microscopy

Spatially patterning the polarization state of a beam enables a novel approach for phase contrast microscopy, in which two foci (sample and reference) are offset along the optical axis. Polarization wavefront shaping is achieved through the addition of two custom microretarter array (RA) 25mm optics, which serve as selective converging/diverging lenses focusing right and left circular polarization components onto different focal planes. Positioning of a matched RA in the transmission path recombines the two polarization components, with phase differences manifesting and rotations in the polarization state. This approach combines benefits of Nomarski and Zernike phase contrast strategies, while minimizing common artifacts associated with each. In addition, polarization wavefront shaping provides a straightforward route for depth of field extension through addition of a single fixed 1” optic.