Orientation independent retardation imaging using quantitative polarized phase microscopy.

Simultaneous optical phase and retardation measurement of a birefringent specimen is demonstrated independently of a priori knowledge of the optic axis orientation. The two-dimensional retardation distribution in both magnitude and angle of the fast axis orientation is uniquely determined from transverse phase images recorded with a bright field transmission microscope using light polarized at a minimum of three different polarization orientations. This approach opens a new possibility for stain-free phase and orientation-independent retardation characterization of samples using only one polarizer without needing other additional optical elements traditionally used in polarimetric measurements.