High-precision SMI microscopy size measurements by simultaneous frequency domain reconstruction of the axial point spread function

An improved size measurement method using spatially modulated illumination (SMI) microscopy enhances subwavelength size determination of fluorescent objects. In this new approach the point spread function of the SMI microscope is reconstructed in each measurement. For this, reference objects with known dye distribution have to be put additionally to the unknown objects on the object slide or on the cover slip. We present data from measurements on fluorescent microspheres with diameters of 140 and 200 nm using an excitation wavelength of 488 nm.