We present a theoretical and experimental research
about applying a very-small-aperture laser (VSAL) to detect
sub-wavelength data. Near-field distribution of a VSAL, which is
essential for the application of such near-field devices, will be
affected by the sample or fiber posited in the near-field region
of the aperture. When the device is applied to detect the
sub-wavelength data, the real resolution depends on the near-field
spot size, the divergent angle of the beam and the distance from
the aperture to the sample. Experimental results, including the
near-field detection of the spot and detection of the
sub-wavelength data by using the VSAL, are presented in this
paper. We realize the two dimensional scanning about the
sub-wavelength data (with the width 600 nm) by employing a VSAL
with a 300 nm×300 nm aperture.