Super resolution computational saturated absorption microscopy

Abstract: Imaging beyond the diffraction limit barrier has attracted wide attention due to the ability to resolve image features that were previously hidden. Of the various super-resolution microscopy techniques available, a particularly simple method called saturated excitation microscopy (SAX) requires only a simple modification of a laser scanning microscope where the illumination beam power is sinusoidally modulated and driven into saturation. SAX images are extracted from harmonics of the modulation frequency and exhibit improved spatial resolution. Unfortunately, this elegant strategy is hindered by the incursion of shot noise that prevents high resolution imaging in many realistic scenarios. Here, we demonstrate a new technique for super resolution imaging that we call computational saturated absorption (CSA) in which a joint deconvolution is applied to a set of images with diversity in spatial frequency support among the point spread functions used in the image formation with saturated laser scanning fluorescence microscope. CSA microscopy allows access to the high spatial frequency diversity in a set of saturated effective point spread functions, while avoiding image degradation from shot noise.