  Spatial effects of interference and interaction of light modes in the
subwavelength part of the near-field optical microscopy probe have been
theoretically studied. It was found that the mode interference can lead to
higher spatial compression of light (lambda = 500 nm in free space) within the
transverse size of 25 nm inside the probe output aperture of 100 nm in
diameter. The results principally demonstrate the possibility of increasing
spatial resolution of the near-field optical microscopy technique.
