Large-field structured illumination microscopy based on 2D grating and a spatial light modulator

Structured illumination microscopy (SIM) has been widely used in biological research due to its merits of fast imaging speed, minimal invasiveness, super-resolution, and optical sectioning imaging capability. However, the conventional SIM that uses a spatial light modulator (SLM) for fringe projection often has a limited imaging field of view. Herein, we report a large-field SIM technique that combines a 2D grating for fringe pattern projection and an SLM for selecting fringe orientation and performing phase shifting digitally. The proposed SIM technique breaks the bottleneck of fringe number limited by the digital projection devices, while maintaining the advantage of high-speed (digital) phase shifting of conventional SIM. The method avoids the pixilation and dispersion effects of the SLMs. Finally, a 1.8-fold resolution enhancement in a large field of 690x517 mu m(2) under a 20x/NA0.75 objective is experimentally demonstrated. The proposed technique can be widely applied to biology, chemistry, and industry. (C) 2022 Optica Publishing Group

Automated summary

Structured illumination microscopy (SIM) is widely used in biological research for its fast imaging speed, minimal invasiveness, super-resolution, and optical sectioning imaging capability. This article introduces a large-field SIM technique that combines a 2D grating and a spatial light modulator (SLM) to achieve a larger imaging field and high-speed digital phase shifting. Experimental results demonstrate an improved resolution in a large field of view.