Tunable structured illumination microscopy for acquisition of partially super-resolved images using a digital micro-mirror device

Abstract

Structured illumination microscopy (SIM) has been developed as a fast super-resolution microscopy technique. However, the reconstruction process of conventional SIM images requires several images, which still limits the imaging speed. Furthermore, all regions in a field of view (FOV) is typically super-resolved with low temporal resolution. In this paper, we introduce a SIM method which enables to obtain partially super-resolved region in a single image using a digital micro-mirror device (DMD). The non-super-resolved regions enables measurement of dynamic processes with high temporal resolution. This technique achieves simultaneous observation with different temporal resolution and spatial resolution in a single image. The illumination pattern is generated by a DMD (DLPLCR6500EVM, Texas Instruments), which consists of 1920×1080 micro-mirrors with 7.56 um pitch. The period of a single fringe pattern is adjusted with the diffraction limit of our system. Using the conventional SIM scheme, three different orientations of the fringe patterned illumination enables isotropic resolution enhancement. Image acquisition was performed with the sample containing moving targets with different speed. Partially fringed patterns were illuminated to the regions including static and comparably slow targets. The other parts containing fast moving targets were imaged with a homogeneous illumination pattern. As a result, we could acquire the partially super-resolved SIM images for the regions containing slow targets. The moving targets could be also imaged by applying this method with diffraction-limited resolution, but with high temporal resolution. Finally, we demonstrate dynamically tunable imaging with variable spatial and temporal resolution across the FOV for imaging dynamics of biological samples.