The point spread function of fluorescence microscopes imaging through a layered or an inhomogeneous medium

摘要

The optical microscope has proven to be an invaluable tool in biology, because of its unique capabilities of 3-D imaging of living specimens. However, compared to other techniques, the achievable resolution is limited. Several techniques have been proposed to improve the resolution of the fluorescence microscope. The confocal set-up is the first of them. Interference effects can also be used to sharpen up the point spread function (PSF) in 4Pi microscopy. Another approach is the so-called STimulated Emission Depletion microscopy, which has permitted to decrease the resolution down to about 100 nm in three dimensions, and below 50 nm in either the x-y plane, or along the z-axis.