Optical‐sectioning improvement in two‐color excitation scanning microscopy

We present a new beam‐shaping technique for two‐color excitation fluorescence microscopy. We show that by simply inserting a properly designed shaded‐ring filter in the illumination beam of smaller wavelength, it is possible to improve the effective optical sectioning capacity of such microscopes by 23%. Such an improvement is obtained at the expense of only a very small increasing of the overall energy in the point‐spread‐function sidelobes. The performance of this technique is illustrated by a numerical imaging simulation. Microsc. Res. Tech. 64:96–102, 2004. © 2004 Wiley‐Liss, Inc.