Standing-wave fluorescence microscopy

Fluorescence microscopy is enormously useful in cell biology and biomedicine because highly-specific probe molecules can be used to label structure or transduce physiological condition within complex cells and tissues. Fluorescence optical sectioning microscopy (FOSM) and confocal scanning fluorescence microscopy (CSFM) are widely used for viewing 3D structure in such labeled specimens. In both methods, 3D data consists of images recorded as the specimen is stepped through focus. Direct image formation in FOSM is fast and relatively efficient, but the spatial frequency band limit of the optical transfer function (OTF) limits axial resolution severely. Computational deconvolution is required to achieve full resolution. Direct spatial filtering in CSFM expands the band limit axially and transversely, but with the tradeoff of lower speed and lower signal-to-noise ratio. Limited axial resolution remains a challenge in both cases.