Resolution and uniformity improvement of parallel confocal microscopy based on microlens arrays and a spatial light modulator.

Abstract

In traditional fluorescence microscopy, it is hard to achieve a large uniform imaging field with high resolution. In this manuscript, we developed a confocal fluorescence microscope combining the microlens array with spatial light modulator to address this issue. In our system, a multi-spot array generated by a spatial light modulator passes through the microlens array to form an optical probe array. Then multi-spot adaptive pixel-reassignment method for image scanning microscopy (MAPR-ISM) will be introduced in this parallelized imaging to improve spatial resolution. To generate a uniform image, we employ an optimized double weighted Gerchberg-Saxton algorithm (ODWGS) using signal feedback from the camera. We have built a prototype system with a FOV of 3.5 mm × 3.5 mm illuminated by 2500 confocal points. The system provides a lateral resolution of ∼0.82 µm with ∼1.6 times resolution enhancement after ISM processing. And the nonuniformity across the whole imaging field is 3%. Experimental results of fluorescent beads, mouse brain slices and melanoma slices are presented to validate the applicability and effectiveness of our system.