Quasi-common-path off-axis interferometric quantitative phase microscopy based on amplitude-division

Abstract

A quasi-common-path off-axis interferometric quantitative phase microscopy (iQPM) is proposed using amplitude-division in this paper. Utilizing a quasi-common-path interferometric module, our method divides the object beam into two copies using a beam-splitter and two mirrors after the output of the microscope, while spatially filters one of the copies to act as the reference beam, and thus yields off-axis interference at the camera plane. The compact module is built using simple optical elements without the requirements of special optical skills and/or complex alignment. In contrast to the previous common-path off-axis iQPMs, the proposed method can flexibly adjust each channel to improve the visibility and/or frequency of the interferogram. Several experimental results are presented to demonstrate the validity and stability of the proposed iQPM.