Frequency and Phase Mismatch Corrections for Imaging Interferometric Microscopy

Synthetic aperture Imaging Interferometric Microscopy (IIM) is a spatial resolution enhancement technique for optical microscopy. The technique involves combining multiple sub-images to achieve the resolution equivalent to that of a higher numerical aperture objective lens. Several image reconstruction challenges, including the frequency deviation in the sub-images and the lack of precision in maintaining mutual phase between sub-images, degrades the final output image quality. This paper proposes methods to correct the frequency deviation in sub-images and maintain the mutual phase between sub-images electronically. Structural Similarity Index Metric (SSIM) is used to compare the final simulation results. The methods are compared for a Manhattan structure of 260 nm spatial resolution with 2-μm pitch calibration grating on all sides. Both of these proposed methods are very useful in improving (by ~ 20%) the output image quality of IIM.