Resolution in three-photon fluorescence scanning microscopy

Resolution in potential three-photon fluorescence scanning microscopy is discussed in terms of the three-dimensional optical transfer function. Images of layers and sharp edges are presented for a comparison of the resolution with that in two-photon fluorescence microscopic imaging. For the same fluorescence wavelength the resolution is almost the same in both cases. However, for a given illumination wavelength the resolution for imaging a thick object in the case of three-photon fluorescence imaging can be improved by as much as 40-50% relative to that in two-photon imaging. (C) 1996 Optical Society of America