Optimized approaches for optical sectioning and resolution enhancement in 2D structured illumination microscopy

The use of structured illumination in fluorescence microscopy allows the suppression of out of focus light and an increase in effective spatial resolution. In this paper we consider different approaches for reconstructing 2D structured illumination images in order to combine these two attributes, to allow fast, optically sectioned, superresolution imaging. We present a linear reconstruction method that maximizes the axial frequency extent of the combined 2D structured illumination passband along with an empirically optimized approximation to this scheme. These reconstruction methods are compared to other schemes using structured illumination images of fluorescent samples. For sinusoidal excitation at half the incoherent cutoff frequency we find that removing information in the zero order passband except for a small region close to the excitation frequency, where it replaces the complementary information from the displaced first order passband, enables optimal reconstruction of optically sectioned images with enhanced spatial resolution.