  We report the direct observation of the electromagnetic-field distribution of
whispering?gallery modes in silica microcavities (spheres and toroids). It is
revealed by their excitation efficiency with a tapered fiber coupler swept
along the meridian. The originality of this method lies in the use of the
coupler itself for the near field mapping, eliminating the need of additional
tools used in previous work. This method is successfully applied to
microspheres and microtoroids
