Interferometric phase microscopy using slightly-off-axis reflective point diffraction interferometer

- Slightly-off-axis configuration is built using a reflective 4f optical system.
- Two carrier interferograms with π/2 phase shift are recorded in one shot.
- The method can take speed, resolution, and stability into consideration.
- Specimen can be measured with full utilization of the input-plane field of view.
- Experiments are done to show the validity and stability of the proposed method.

An interferometric phase microscopy (IPM) is proposed using slightly-off-axis reflective point diffraction interferometry for quantitative phase imaging. A retro-reflector consisting two mirrors is used to generate an angle between the object beam and reference beam, and a 45° tilted polarizing beam splitter is used to split the horizontal and vertical components of the both beams. Two carrier interferograms with π/2 phase-shift can be acquired in one shot, and the phase distribution of a thin specimen can be retrieved using a fast reconstruction method. The new IPM without loss in the utilization of the input-plane field of view combines the real time and optimizing detector bandwidth measurement benefit associated with slightly-off-axis method, high stability associated with common path geometry, and simplicity in terms of procedure and setup. Experiments are carried out on both static and dynamic specimens to demonstrate the validity and stability of the proposed method.