Amplitude Analysis of Polarization Modulation Data and 3D-Polarization Demodulation (3D-SPoD)

Super-resolution optical fluctuation imaging (SOFI) is a technique that uses the amplitude of fluorescence correlation data for improved resolution of fluorescence images. Here, we explore if also the amplitude of superresolution by polarisation demodulation (SPoD) data can be used to gain additional information about the underlying structures. Highly organized experimental as well a simulated actin filament data demonstrate a principle information gain from this approach. In addition, we explored theoretically the benefits of analyzing the entire 3D-polarization information instead of only 2D-projections thereof. Due to fundamental principles, the probability of finding parallel orientations is approaching zero in 3D-SPoD in contrast to 2D-approaches. Using the modulation-amplitude based analysis we explored systematically simulated 3D-single molecules data (for which the true structures are known) under different conditions that are typically observed in experiments. We found that this approach can significantly improve the distinction, reconstruction and localization. In addition, these approaches are less sensitive to uncertainties in the knowledge about the true experimental point-spread-function (PSF) used for reconstruction compared to approaches using non-modulated data. Finally, they can effectively remove higher levels of non-modulated back-ground intensity.